Maemo is being officialy maintained by ScummVM, I've already repported the the keyboard and volume keys issues on the N900:
http://forums.scummvm.org/viewtopic.php?t=11077
tsoliman already made a fix for the keyboard problem and I applied a patch for the volume keys from version 1.3.1. I've also added a shotcut for the in-game menu:
ctl+volume+
Here is the debian package I build with those fixes:
http://ubuntuone.com/2Ld09WoFHzHR3UIJrLRVQg
(I couldn't wait to plan Lands of Lore on my n900 )