I was really thinking it would be a candidate for the gas / glow conversion. This way you eliminate the flywheel and coil. You still need a prop adapter however.

The pocket bike engines I've seen have the cyclinder and carb almost 180 deg opposed. This means that if you like to mount your cylinder pointing down your carb is nearly on top of the engine where it can be more accessible. A good Walbro carb can be had pretty cheaply to replace the stock one. It also appears that the clutch mounting area would be ideal for a backplate mount. Given that there are probably many people working on hop ups I would think some technical know-how is already in the works.