This may not help, but all I can think of right now is this:
How did you check for spark? There may be some way the spark is prematurely jumping before it hits the end of the plug. When you check for compression, it gives a nice proper dry pop? There are ports in most engines that help to lubricate everything and somehow the problem could lie there, because if the starting fluid isn't getting to where the piston pushes it to pressurize the chamber, then that might very well be it. I'm not sure which way you're doing the whole starting fluid thing, so I may not be any help at all. I've asked MopedCam if he has any clue, and he also mentioned you might try what we call "cracking it out". Basically, pull the plug out, take a cigarette lighter (if you fear for the safety of your fingers, a barbecue pit lighter) and ignite it at the plug hole. If the fluid has been getting into there, you should get a nice pop, or at LEAST a small flame from the hole. Hope I helped at least a little!
swarm and destroy