AFAIK leetnoob was able to enable EasyDebian's totemplayer to play HW accelerated videos, by copying some files from Maemo to ED (possibly replacing some ED's ones). It's buried "somewhere" in this thread, and I'm perfectly sure it was really working, not just a hoax.
I'm perfectly sure, that You can set ext4 to lack journal, thus - this time for sure - benefit from ext4 optimizations, even if You prefer journal-less filesystem.
Of course I understand that You may like to wait for Wheezy becoming stable, but as for compiling on-device, as different problem - why You can't do it because of watchdog? Your device becomes uresponsive and watchdog triggers reboot, or what?
If the latter is true, remember, that by using swap on microSD + correct swap-related settings (to be found in last few pages here, 2 different settings, suggested by freemangordon and by me), You could probably do it on device without bad surprises. At least, it works for me even during heavy compressing (lzma) operations, both memory and CPU requiring.