Here is the current jaxp/jaxws JDK7 layout (corba too, mostly):

  ./ASSEMBLY_EXCEPTION
  ./LICENSE
  ./README
  ./THIRD_PARTY_README
  ./TRADEMARK
  ./make/Makefile
  ./make/build.properties
  ./make/build.xml
  ./make/jprt.properties
  ./make/tools/StripProperties/
  ./src/share/classes/{com,javax,org}

Since the source bundles will need to be public, I'm thinking
of moving the ant build script to the top, getting rid of
./make/tools/StripProperties, and also the "share/classes"
in the source path.

So we would end up with something like:

  ./ASSEMBLY_EXCEPTION
  ./LICENSE
  ./README
  ./THIRD_PARTY_README
  ./TRADEMARK
  ./build.properties
  ./build.xml
  ./make/Makefile      -  will need to run: cd .. && ant
  ./make/jprt.properties
  ./nbproject/         - NetBeans project files (new)
  ./src/{com,javax,org}

And the ./src/ would eventually represent the bundled up sources.
If the src/ delivery included it's own build.xml, that could be
used by the JDK's build.xml for this repository.
Multiple source bundles could be exploded into src/ too.

The custom JDK build procedures can be in
the top level build.xml or the make/Makefile.

On corba, the build is more complicated due to the idlj use during
the build, but I can see how the proposal above can work too, assuming
we toss the native library and the one native source file:
   corba/src/share/native/com/sun/corba/se/internal/io/ioser.c