Hi Rusty;
        Have you looked at Freedom motors? They've been around for awhile now but I don't know if they are actually producing any motors yet. Last year they were claiming to be about to begin selling them. Don't know if they actually have. Prices are $5000 and $7000.  IIRC the output was something like 75hp & 150hp. They are related to the Moller Skycar, so I don't know what that does for their credibility?

        At least they are a modern engine and parts availability shouldn't be an issue if the company succeeds.
        On the other end of the scale... Back in the early 70's when over a hundred manufactures built a snowmobile (Harley, Avon, to name a few, hmmm I wonder if Tupperware got into it?:-), there were a few with rotary engines in the 35-45hp range. Arctic Cat was probably the most successful of these. I did a search and found a link to one on e-bay but the link was dead. It may be fun to play with one of these but you'd better be good at making parts on that mill of yours! Not too sure I'd like to fly behind one.

S. Todd Bartrim
Turbo 13B
RX-9endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

        "Imagination is more important than knowledge"
                                        -Albert Einstein