I agree with you on the long rod setup. The higher you can get the wrist pin to the top of the piston the better. At the same time You can also increase the stroke of the crank to get more torque at a lower rpm range. You would have a very flat torque curve(Ideal for our use)
As far as detonation, you can control that with compression(More is best) and hi octane fuels (110 low lead). and ign. timing (like multiply spark) Piston design now comes into play to help stop detonation. A design like the nascar guys are using. Swirl technology and fast burn cylinder design is now coming of age. The better we can atomize the fuel charge the more power we get without detonation. no detonation, more torque!! And to top it all off we would get longer run times / oz of fuel.

I will problably be one of the first to buy a stand alone fuel injection unit for Gassers when they come out. It's just a matter of time before they do.
ttyl