There are going to be very few premade distros that do that. You could make it do it yourself with some work.
I doubt you'll find "featureful" ones anyways, since they are designed to actually fit in your RAM which usually needs its space. running a fancy os in RAM means fitting those features in memory, as storage as well as a running program. Do you have that much RAM?
DSL is great because it's small. Granted, it's tiny and featureless, but it's actually small enough to fit into RAM, being only 50 MB. Gnome alone is, what, 200 MB of disk space, plus at least another 50 MB running? (Made up optimistic numbers on the spot)