I would love to do a dreamcast. I have already a design in mind when I get one. I do retro consoles because they are cheap to pick up. I dont think I would make good profit if I would buy, paint and sell modern consoles. There is also a bunch of guys out there that paint 360 and ps3 controller and consoles. There is also colorware that has excellent finishes but they are very limited. Its kinda like asking a regular car painter to do airbrushing, flake paint jobs, candys or pinstriping.
Yes it is possible. I have painted a few rumble packs for the n64 but its a very tight fit. The paint will not peel off but it will get scratched. I dont really know how it is on the dreamcast because I dont own one.