May i suggest something, I am not a linux expert but instead of starting Aros from xwindow, maybe it will be better from command line, i mean dont start xwindow at all, you still lose memory and maybe speed.
Also Debian is still not compiled with floating point acceleration for Pi, Debian with floating point support on Pi hardware will be available later, I bet when it will be done your Aros will get a massive boost.
I dont know Aros, but know Amiga since I got an Amiga 500/2000 few years ago
, Aros is a Amiga emulator? or its the real amiga source compiled in linux and to run from linux?
Anyway, nice project, I will install that if I receive my Pi one day!