I was able to provide syntax highlighting for java trivially by extending the NShader project. I may be able to use the java compiler in Ja.NET to "scan" the java for tokens however when i tried this i got an exception so I just used lex.
I would also be very interested in helping with Visual studio integration. We may be able to provide something similar to the IronPython integration project (See visual studio sdk). This would be a pretty impressive package to start pushing.
Stephen