I'm guessing this would be a good candidate for a Banshee extension. If it's already written in Java, I'm guessing the "core" code could be pretty easily ported to C#/Mono if you're familiar with both. (I'm not, so I won't be any help there, and my estimation might be off. ;)
This is the place to ask for help if you're thinking about developing something (also see here:
http://banshee-project.org/contribute/write-code/), but if you just want to file an enhancement request for the feature, you can do that here:
http://banshee-project.org/contribute/file-bugs/
Cheers,
Andrew