They don't "require" a physical examination at my local DMV office in Virginia, MN. I'm not sure if it is the same throughout the state, but they basically told me they don't want to go inspect it any more than I want them to come inspect it. There are a few categories and you have to have a certain number of items from each one (potable water, heat seperate from the engine, etc) much like your electives in college.
As for the cost of registration in Minnesota...we go by weight. Recreational vehicles are subject to the same tax schedule as commercial plates (Y-plates) and it goes in 3000 lbs increments. I have not yet re-registered mine as I'm waiting to finish the conversion and run across some scales to see how much it weighs. The fee schedule can be found on the link below.
Any additional Minnesota State Statute can be found at this link.