well I recently asked the dude who working on a kaillera enabled version of Snes9x known as Snes9k to make similar changes if possible.
in short, we may be lucky to see a the next version support quiting the emu using esc in fullscreen... but again, I got no confirmation on this so we'll just have to wait for the next version and see.
as for gens+, recompiling a version with different key support is pretty trivial if its based on Gens 2.12. e.g. even I might consider doing it every release featuring major enhancements. The AVGA version is a tad more tricky, but as I own two of the damn things, you'll know that I'll want it to work!

I'm looking at the source now!