yep, they are made by headline (http://www.headline-motor.com) but i'm not sure they'll sell it to you direct. you can buy one from paco (cyclone taiwan). he has them in stock.
i'm also trying to adapt the cyclone gearbox for my HXT 130. it requires a 9T 12mm pinion input so i ordered one of these http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMGY1. haven't received it yet so don't know if it's a match. need to turn the shaft down to 5mm to fit this pinion. i'm making my own faceplate to mate the gearbox to motor. nice thing with the cyclone..you can use their 1-way roller bearing / fw adapter / dual freewheel out of the box.
i've also toyed around with the idea of using dual matex 75M series gears: http://matexgears.thomasnet.com/viewitems/all-categories/torque-range-45-300in--lbs-?&forward=1
more work and expense going this route with the benefit of higher torque rating (here's a cracked cyclone gearbox http://bushnell.homeip.net/~bill/bike/pictures/cyclone_motor/index.html)
finally, you could also try banebots p80: http://banebots.com/c/P80K-nnnn-0005. they are longer than the cyclones so it might be tough to fit motor + gearhead between the cranks (even with extended spindles).
anyone have any experience adapting the matex gears?