diff --git a/src/java/com/threerings/io/FieldMarshaller.java b/src/java/com/threerings/io/FieldMarshaller.java
index ce230a726..eaddb47fb 100644
--- a/src/java/com/threerings/io/FieldMarshaller.java
+++ b/src/java/com/threerings/io/FieldMarshaller.java
@@ -22,9 +22,13 @@
 package com.threerings.io;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
 import java.util.Date;
 import java.util.HashMap;
 
+import static com.threerings.NaryaLog.log;
+
 /**
  * Used to read and write a single field of a {@link Streamable} instance.
  */
@@ -53,6 +57,25 @@ public abstract class FieldMarshaller
             createMarshallers();
         }
 
+        // first look to see if this field has custom reader/writer methods
+        Method reader = null, writer = null;
+        try {
+            reader = field.getDeclaringClass().getMethod(
+                getReaderMethodName(field.getName()), READER_ARGS);
+            writer = field.getDeclaringClass().getMethod(
+                getWriterMethodName(field.getName()), WRITER_ARGS);
+            return new MethodFieldMarshaller(reader, writer);
+        } catch (NoSuchMethodException nsme) {
+            // no problem
+        }
+        if ((reader != null || writer != null) && (reader == null || writer == null)) {
+            log.warning("Class contains one but not both custom field reader and writer " +
+                        "[class=" + field.getDeclaringClass().getName() +
+                        ", field=" + field.getName() + ", reader=" + reader +
+                        ", writer=" + writer + "].");
+            // fall through to using reflection on the fields...
+        }
+
         Class ftype = field.getType();
         if (ftype.isInterface()) {
             // if the class is a pure interface, use Object.
@@ -70,6 +93,24 @@ public abstract class FieldMarshaller
         return fm;
     }
 
+    /**
+     * Returns the name of the custom reader method which will be used if it exists to stream a
+     * field with the supplied name.
+     */
+    public static final String getReaderMethodName (String field)
+    {
+        return "readField_" + field;
+    }
+
+    /**
+     * Returns the name of the custom writer method which will be used if it exists to stream a
+     * field with the supplied name.
+     */
+    public static final String getWriterMethodName (String field)
+    {
+        return "writeField_" + field;
+    }
+
     /**
      * Used to marshall and unmarshall classes for which we have a basic {@link Streamer}.
      */
@@ -110,6 +151,34 @@ public abstract class FieldMarshaller
         protected Streamer _streamer;
     }
 
+    /**
+     * Uses custom reader and writer methods to read and write a field.
+     */
+    protected static class MethodFieldMarshaller extends FieldMarshaller
+    {
+        public MethodFieldMarshaller (Method reader, Method writer)
+        {
+            _reader = reader;
+            _writer = writer;
+        }
+
+        // documentation inherited
+        public void readField (Field field, Object target, ObjectInputStream in)
+            throws Exception
+        {
+            _reader.invoke(target, in);
+        }
+
+        // documentation inherited
+        public void writeField (Field field, Object source, ObjectOutputStream out)
+            throws Exception
+        {
+            _writer.invoke(source, out);
+        }
+
+        protected Method _reader, _writer;
+    }
+
     /**
      * Creates instances of all known field marshaller types and populates the {@link
      * #_marshallers} table with them. This is called the first time a marshaller is requested.
@@ -240,4 +309,10 @@ public abstract class FieldMarshaller
 
     /** Contains a mapping from field type to field marshaller instance for that type. */
     protected static HashMap<Class,FieldMarshaller> _marshallers;
+
+    /** Defines the signature to a custom field reader method. */
+    protected static final Class[] READER_ARGS = { ObjectInputStream.class };
+
+    /** Defines the signature to a custom field writer method. */
+    protected static final Class[] WRITER_ARGS = { ObjectOutputStream.class };
 }
diff --git a/src/java/com/threerings/presents/tools/InstrumentStreamableTask.java b/src/java/com/threerings/presents/tools/InstrumentStreamableTask.java
index 5eed6a58a..ef621b5cf 100644
--- a/src/java/com/threerings/presents/tools/InstrumentStreamableTask.java
+++ b/src/java/com/threerings/presents/tools/InstrumentStreamableTask.java
@@ -45,6 +45,7 @@ import org.apache.tools.ant.types.FileSet;
 import org.apache.tools.ant.types.Path;
 
 import com.samskivert.io.StreamUtil;
+import com.threerings.io.FieldMarshaller;
 import com.threerings.io.Streamable;
 
 /**
@@ -154,8 +155,6 @@ public class InstrumentStreamableTask extends Task
     protected void processStreamable (File source, CtClass clazz)
         throws NotFoundException
     {
-        // System.err.println("Processing " + clazz.getName() + "...");
-
         ArrayList<CtField> fields = new ArrayList<CtField>();
         for (CtField field : clazz.getDeclaredFields()) {
             int modifiers = field.getModifiers();
@@ -173,13 +172,13 @@ public class InstrumentStreamableTask extends Task
 
         int added = 0;
         for (CtField field : fields) {
-            String rname = "readField_" + field.getName();
+            String rname = FieldMarshaller.getReaderMethodName(field.getName());
             if (!methods.contains(rname)) {
                 String reader =
                     "public void " + rname + " (com.threerings.io.ObjectInputStream ins) {\n" +
                     "    " + field.getName() + " = " + getFieldReader(field) + ";\n" +
                     "}";
-                // System.err.println("Adding reader " + clazz.getName() + "." + rname);
+                // System.out.println("Adding reader " + clazz.getName() + "." + rname);
                 try {
                     clazz.addMethod(CtNewMethod.make(reader, clazz));
                     added++;
@@ -189,9 +188,10 @@ public class InstrumentStreamableTask extends Task
                     System.err.println(reader);
                 }
             }
-            String wname = "writeField_" + field.getName();
+
+            String wname = FieldMarshaller.getWriterMethodName(field.getName());
             if (!methods.contains(wname)) {
-                // System.err.println("Adding writer " + clazz.getName() + "." + wname);
+                // System.out.println("Adding writer " + clazz.getName() + "." + wname);
                 String writer =
                     "public void " + wname + " (com.threerings.io.ObjectOutputStream out) {\n" +
                     "    out." + getFieldWriter(field) + ";\n" +
@@ -209,6 +209,7 @@ public class InstrumentStreamableTask extends Task
 
         if (added > 0) {
             try {
+                System.out.println("Instrumented '" + clazz.getName() + "'.");
                 clazz.writeFile(_outdir.getPath());
             } catch (Exception e) {
                 System.err.println("Failed to write instrumented class [class=" + clazz +