What 5.5ft camper? If such a thing exists, it must be fairly new on the market.
Last I knew there was no such thing.
5.5ft beds are achieved by lopping the front 12" off of a 6.5ft bed. Most of the bed hangs behind the rear axle, with only about 18" ahead of the rear axle. Very tight space to cram enough weight into to get the camper to balance anywhere near over the axle.
Before you say "what about the cabover" let me point out that while cabovers do contribute to the location of the COG, there is only so much you can put up there to move weight forward. It's not like you can move the water tank, refrigerator, sink, toilet, propane, etc. into the cabover to achieve balance.
