Gantz

Id like to see a system for 4.0 for the gantz universe. think anyone is up for the challenge?

Try any open system that uses skills instead of classes. I'd say Paranoia is better at Gantz than D&D

You would have to work pretty hard to make 4e work for Gantz, but if you want a D&D-ish system then D20 Modern could easily be adapted for this purpose. You could probably do it in an afternoon.