Doesn't do much right now except rendering an uploaded sysex file.
The code side itself is a tad more advanced, I can convert md patterns and md songs to midi, and back. It keeps the param locks as well, so you can draw curves in your sequencer, and then the conversion software tries to approximate it with slides etc... Also it can convert longer midi files into a song, using some intelligence in splitting it into patterns. Also as I can write back the data structures to sysex, I plan to do some web2.0 librarian, where you tag machines, and then can drag'n'drop them into a complete kit.
A nice thing also is that it can convert melodic lines back to TRX-BD, etc... according to
http://www.gweep.net/%7Eshifty/machinedrum/ptch/sps1.png (and also on ROM-machines).
So I guess a lot of potential
But the hacking on that "simple" webapp thing made me realise that there is quite a lot of work hidden there.