I'm currently making a emulator for a virtual 8 bit machine. It has a display and 64k of ram.
I had a go at putting uLisp onto it.
It went pretty well. It's pretty harsh to use at the moment because you have to write everything correctly without backspacing, but with a line editor would make a pretty nice repl.
The emulator in it's current state is at http://fingswotidun.com/avr/
I added moveto lineto and colour to the builtin functions so you can do some drawing.