What is really, really needed is a small radial that can replace the Warner's that used to appear on Monocoupe's, Great Lakes, the baby Waco's, etc. I'd really love for something in the 185-250hp range that was light. I think the prop wouldn't be a really hard deal but we desperately need a motor like that to replace the Warner's. I've seen some Great Lake's, a Skybolt (I believe) and others with a 220 Continental and I've seen a Fairchild 24 with a 245 Jacobs - but they don't look quite right - and heavy. I need Rotec to create something, or perhaps someone to buy the Type Certificate for the old Warner's and start making them again.
The reason is - the old Warner's are getting tough to find parts for. Second - you could have an incredible crop of homebuilts that could spring up around an engine such as this. I'm thinking of variants of airplanes like the Flagg F-13 and such that would just really kick ass and have a radial that you can get parts for.
Here is the Flagg. It was a built in 1933. Now - imagine this machine - 185hp Warner - and then imagine how many cool designs could be created if there was the engine I describe. A 220 Continental would be too big obviously for this airplane - but the Rotec would be too small - and the commie motor (Vendeneyev) probably wouldn't work either (I think its physical dimensions are closer to the Continental/Jacobs and I think the accessory section for that motor might not work on something like the Flagg).
Here's the Flagg - let your imagination run wild on the designs that could had if that motor existed: