I am in the market for a plane and would prefer a rotary-powered, as I have lots of experience working with rotary engines.  As a bonus, homebuilt planes all seem to get about twice as much fuel economy as factory built planes.  So that is nice too.  I know there are a few rotary powered planes available for sale, but not too many.

I have neither the time nor desire to build my own plane, so my question is more about maintenance and inspections.  I'm not an official A&P and I don't know if I will be able to find an A&P to work on a home built plane with a car engine in it!  I am happy to do engine maintenance, but am not entirely clear on the legality of it, since I would not be the original builder.

Similarly when it is eventually time for an engine rebuild, would I be able to remove the engine, take it down to Atkins (who are not far from me) and have them rebuild it, or rebuild it myself, and then reinstall it, and find an A&P to just sign off on the work?

Plan B is to buy whatever plane even if it has a Lycosaurus, but when time for overhaul comes, get rid of the Lycoming and replace it with a rotary.  Thought in this case is to get the rotary tuned, a little broken in and running on a stand in the hangar in advance, so that when the time comes to do the swap it can be done with a minimum of downtime.  (I know it cannot really be tuned for altitude in this way but it is better than nothing!).  But again, the fact that I would not be the original builder makes me worry about legalities.  I have heard that this has been done so question is more about the how.

I do not really understand all the law involved and hopefully somebody here can help.  Thanks!