Assuming you have 68k with MMU and enough memory you're set (well true there is uClinux which works without MMU but I doubt it'd be very useful here).
It will be very slow, but you should be able to run X. Do note that most distros have dropped the official 68k support, so you might need to either use very old distribution or do fair bit of hacking yourself.
Is it worth it? IMO no. You'll be much happier with a x86 box running it. Even older x86 machine will be ok.
