For Diablo you can install it by directly clicking scummvm .deb file from any repository. So far there is same binary for OS 2006,7, and 8. http://repository.maemo.org/extras/pool/chinook/free/s/scummvm/
As for autobuilder - yes in theory, unfortunately scummvm has quite a lot of dependencies so it is not exactly trivial and I prefer spending time on improving real code than debian packaging of dependencies. See also http://www.gossamer-threads.com/lists/maemo/developers/38141#38141
0.12 release is near so I will look at it when making 0.12

Essential if you like 'old-school' adventure games, Very enjoyable on tablets.