What are the other dimensions, would it be 2ft deep and 2ft high as well?
Without a run attached, to be honest I'd still say 2 comfortably, and an absolute maximum of 3 at a push. 8*2 is still only 16 square feet, which isn't a lot for a number of buns.
If there was a run attached I would say 3+ (depending on size of run etc) but without attached run I'd still say 2, as with the best will in the world, the rabbits are still going to be in the hutch for, say, 16 hours a day, including dawn and dusk when they are most active.