diff --git a/rebundle.js b/rebundle.js
index 134e3e1b2c..68c75979c7 100644
--- a/rebundle.js
+++ b/rebundle.js
@@ -3,29 +3,53 @@
 
 var glob = require('glob'),
     fs = require('fs'),
-    header = fs.readFileSync('header.txt', 'utf8');
+    _ = require('lodash'),
+    template = _.template(fs.readFileSync('template.txt', 'utf8'));
 
-function indent(str) {
-    return str.split('\n').map(function (line, index) {
-        return index === 0 ? line : ('    ' + line);
+function indent(str, depth) {
+    return _.trimLeft(str.split('\n').map(function (line) {
+        return _.repeat('    ', depth || 1) + line;
     }).filter(function (line) {
         return line.trim().length > 0;
+    }).join('\n'));
+}
+
+function findImpls(bundleContents) {
+    return _(bundleContents.extensions || {})
+        .map().flatten().pluck('implementation').filter().value();
+}
+
+function toIdentifier(impl) {
+    var parts = impl.replace(".js", "").split('/');
+    return parts[parts.length - 1];
+}
+
+function toPath(impl) {
+    return "\"./src/" + impl.replace(".js", "") + "\"";
+}
+
+function replaceImpls(bundleText) {
+    var rx = /"implementation": "([^"]*)"/;
+    return bundleText.split('\n').map(function (line) {
+        var m = line.match(rx);
+        return m !== null ?
+                line.replace(rx, '"implementation": ' + toIdentifier(m[1])) :
+                line;
     }).join('\n');
 }
 
 function rebundle(file) {
     var plainJson = fs.readFileSync(file, 'utf8'),
+        bundleContents = JSON.parse(plainJson),
+        impls = findImpls(bundleContents),
         bundleName = file.replace("/bundle.json", ""),
         outputFile = file.replace(".json", ".js"),
-        contents = [
-            header,
-            "    legacyRegistry.register(\"",
-            bundleName,
-            "\", ",
-            indent(plainJson),
-            ");\n",
-            "});\n"
-        ].join('');
+        contents = template({
+            bundleName: bundleName,
+            implPaths: indent(impls.map(toPath).concat([""]).join(",\n")),
+            implNames: indent(impls.map(toIdentifier).concat([""]).join(",\n")),
+            bundleContents: indent(replaceImpls(JSON.stringify(bundleContents, null, 4)))
+        });
     fs.writeFileSync(outputFile, contents, 'utf8');
 }
 
diff --git a/header.txt b/template.txt
similarity index 86%
rename from header.txt
rename to template.txt
index fb2ba2b096..cddaceba08 100644
--- a/header.txt
+++ b/template.txt
@@ -21,5 +21,14 @@
  *****************************************************************************/
 /*global define*/
 
-define(['legacyRegistry'], function (legacyRegistry) {
+define([
+    <%= implPaths %>
+    'legacyRegistry'
+], function (
+    <%= implNames %>
+    legacyRegistry
+) {
     "use strict";
+
+    legacyRegistry.register("<%= bundleName %>", <%= bundleContents %>);
+});