It has been a while since I asked that question. I wrote it when I was flying the Wattage planes 370 power setup Since then I have found two others. I used the MP Jet 5:1 gearbox and a speed 300. I also started buying, flying and becoming a fan of GWS airplanes. (edit) Forgot to add that I no longer have any broken gear problems. The MP Jet is sturdy as an ox (geared version) and the GWS just has the gear pop forward on a hard nose-in. No more broken gears (/edit)

I have found several sources for gears, but all of them are more expensive than hobby sources. Still searching.