You should look into the piers they use for mobile homes. They're technically jacks.
You get a metal support stand that's usually bolted or resting on a
concrete pad/patio stone somehow, then you buy a jack piece which threads down the center, and you adjust it with a wrench. Each one of these are rated to lift 6000lbs.
http://mobilehomepartsstore.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PAP
The main issue with tiny homes on wheels, as with mobile homes, is that sometimes they have to comply to a wind/hurricane/tornado threat to have them tied down to the ground. If they don't need to be tied to the ground, then these easily function as leveling jacks as long as there's
enough of them.