Awesome work. The sound issue is not related to this package only. Sadly sld-mixer from repos supports only .wavs (check this thread:http://talk.maemo.org/showthread.php?t=81792) so either statically including proper one is needed, or some other gymnastics. Could you by any chance have a look at Armagetron Advanced? With software GL it is close to playable in speed terms and would be awesome multiplayer game for N900 (except for speed everything else works)
http://forums3.armagetronad.net/view...hp?f=4&t=21548 (link to the GLES discussion on upstream forum, sadly devs from there seem to have abandoned the idea)
https://code.launchpad.net/~aavoodoo (link to the close to finished GLES rewrite;opengles iirc is closer, gles2 bit further away)

EDIT: oh and btw, probably worth notifying upstream of your work, doubt they will reject piece of code that widens the possible user-base of their project in such a way (open-pandora, iphones... lots of gles only devices)