If you go out and buy everything the way you are suggesting, a conversion is no deal. I built a 45 CC homelite conversion with a CH ignition. I also have a DA-50 and a ZDZ-80. The conversion is a nice project and I had fun with it, but it is not in the same league as the DA-50 or the ZDZ-80. A conversion works because you get a good deal on the core engine, or because it gives you satisfaction to build it, or because you want to connect the world of general purpose 2-cycle engines to the world of model aircraft engines. In my case it was all three. If you're trying to make a killing in the engine market, you are in for a disappointment, I beleive. Conversions also require tinkering. The muffler I bought from a well-known vendor uses thread-in pipes. These quickly vibrated out, despite my using engineering cement to hold them in. I had to go get them aluminum welded, and I am still nervous about them. Additionally, conversions often have lower standards than the top engines do. For example, my Homelite has a single stud mounting the prop. My DA-50 has a threaded crankshaft plus four cap screws. The DA-50 is ported to run at low RPMs and high torque. The Homelite is not. The one place you can do well is to buy the engine cheaply, and then keep the conversion cost low, by leaving the magneto in place, etc. Cheaper airplane engines like Zenoah are set up this way, and our conversions do tend to resemble them more. I went the "whole route" because I wanted to see what I could do on my own, and I wanted to understand the relationship between a chainsaw engine and a model airplane engine at a higher level than most of the guys at the field do. BTW, one of the better pilots where I fly is a mechanic in a shop like yours. He keeps talking about building a conversion, but he flies a DA-100. I like my conversion and I am glad I did it, but I have no illusions about it. Finally, if you like the idea, get busy and build one. Then tell us about it!