I'm sure you could do this as you could do it in any vehicle. What should concern you the most is trusting your workmanship in the event of a collision. What would the insurance company say about your modification?
I agree, That's the tricky part.
From what I've seen, the bottom plate connects to the floor bolts, although an adapter plate might be required to match the holes. Seems like a flat plate of steel with some holes made to adapt would be pretty safe.
A second flat plate to adapt to the OEM seat slides would do it. What intrigues me is that you can order the pedestals in various heights so it would be easy to make the whole thing strong and solid. Wires would have to be dealt with.
I've seen RV driver seat pedestals for a lot less than a eurocamper swivel.. and it's a complete base that swivels!
Seems like if you call it an RV, many of the safety standards are much less stringent, like the back passenger seats - a wooden bench with lap belts bolted to the floor! In CT, there is not an RV class of registration so I'm not sure how to get insurance to recognize a PM-RV as one.
Ed