Check how much space is taken up by the ramp - some double hutches you end up with less space than if you had a slightly bigger single one. Also, depending on the size of the buns you can always put a shelf at one end. My two are mini lops, and in the hutch they're in whilst we're away (4'x2'x2', but 24 hour access to a VERY big run via runaround tunnels), they have a snuggle box that's about 12" wide by 12" high (x20" deep). The roof of it is low enough for them to jump onto and they spend as much time sitting on it as in it.
ETA, Lol Jenova you beat me! You can get big single hutches on long legs from a lot of places. I'm really missing the tall hutch they have at home, the one they're in up here is really low!