1. 5th Wheel toy haulers are usually designed to carry motorcycles, ATV's or cars in the bay. That should be more than comparable to your product weight.
2/3. We tow a 23k pound 41 foot fifth wheel with a Ford F450 diesel dually with plenty of power for hills.
4. If you want to make sure that you have a trailer that meets all of your needs, check out Motomover | New Horizons RV | Luxury Full Time RV & Custom Fifth Wheels
. You can take a design and customize it to your needs, more/less cabinets, drawers, shelves, floor space. Depending on the weight you are carrying, I would suggest disc brakes on the trailer. You can even get anti-skid brakes these days on the trailer.