I believe Ubuntu MID is no longer a supported platform
I understand what you're wanting and I too am dissapointed in what has been available as most interfaces like this are based on distros that are too bloated for older machines. I think I've tried all of them on older spec system and they dissapointed. You may be interested in following this development:
http://www.murga-linux.com/puppy/vie...864561&t=50563. If Puppy had such an interface it would be ideal