Agreen, thanks for the response, though I don't think you fully understood me. Of course I am going to build what I want, but since this is a first build, and I don't have the option to take up a workbench/garage for weeks, I need to figure out practical options of what to choose.
First off, I have thrown out the idea of buying the cheap $150 2-stroke SkyHawk kit. I might get one of those later on for a super cheap build to tinker on (and maybe a great option so a friend can ride with me occasionally). But I will worry about that another time.
So the HF 79cc predator engine should be able to mount to the GEBE mount kit with relative ease? Do you think I'll need anything else to make this work with the kit? (I'm hoping to complete the build in a day or two once I acquire all the parts, so it's important I plan/prep as well as I can). I'm worried it might be a little large, but if that kit will hold it, since it's a rear mount, I guess that shouldn't be too much of a concern. I'm also a little concerned that it may be a little loud... but hoping that's something with a little tuning and additional parts, I may be able to reduce noise a bit. I love the abundance of resources on the HF 79cc, it seems like it'll be a great pick.. and it's only $99 from Harbor Freight (plus I happen to live only a couple of mile bike ride from a HF store). I'm also a little concerned with the way this kit applies power to the wheel, definitely seems like some really serious spokes will be needed. I'm thinking it may be good to buy a rear wheel from them (tho I suppose if the bike I buy has a wheel that works, maybe I should go with that, and then if/when something goes wrong, get a new wheel... either one they offer, or if I find something even sturdier, go with that)
If the GEBE kit didn't work with the HF 79cc, I also found a pretty cool rear mount, chain drive kit from these guys http://www.thatsdax.com/KIT_REAR_MOUNT_CHAIN_DRIVE.html
I her good things from them (their kits, and support are apparently much better than their website building skills).
Anyway, getting pretty excited about this, now if only I could find a solid bike. Luckily I'm in the SF Bay area where there are lots of used bikes for sale (Tho tons of people seem to want $10 less than the bike cost brand new... even for older 10+ yo bikes... but those people I don't even bother with)... sadly almost no one is responding from craigslist, not to mention, I have yet to find something that really stuck out to me. I think a 26" inch steel frame, with front suspension mountain bike or commuter is gonna be my first choice right now. I also need to look into what I need, and how much effort it takes to convert these mountain bikes or similar inso single speeds (presumably that will make things much easier to add a motor to). I actually have a pretty nice Felt single speed steel frame road bike (but I ride it as a Fixed gear with clip ins and no brakes... so planning on leaving that as it is, I love riding it).
Thanks again for the help, all advice is welcome.