Mike, in first place, I didn't plan to use the engine for anything more than mildly aerobatic, and that, in the best case. Those engines seem good at swinging a big prop and having a very cheap operating cost (making them good for big scale planes like Pipers, towers and such, perhaps something a bit wilder). In second, I'm going to update my signature.

I've just been searching for chainsaws in ebay and it's been discouraging for several reasons.
To begin with, I don't know what stuff is good to be converted, no idea what brand or model to search for and what is a reasonable price. Yup, if you have a mill and lathe you could convert nearly everything, but that's not my case (some engines may also be a bad choice or have low power).
So I do a search by price range, and realize they are not even close to the 45$ a fellow rcu memeber paid for a 55cc chainsaw (going for 99$ with a couple of days left). But even if I was lucky enough to find a deal, I couldn't bid for it - shipping only to the US.[:@]
It really kills my desires to experiment with gassers.[]