Using cheap drill gearboxes with kit motors

[sanddrag]

Has anyone experimented with using the gearboxes from cheap drills made in China (sold through Harbor freight). Dewalts are great, but the are still $100. These things are $20. I've seen them used in BattleBots (or RobotWars or whatever). Has anyone tried to adapt a kit motor (FP, CIM, Globe, Mabuchi) to one of them?

EDIT: Yes, I forgot about Ryobi. I have shifted my Ryobi 18 volt on the fly many times. It wasn't under load but it shifts in both directions while running just superbly. I think the $20 drills from China are only 1 speed but I was mainly looking for reduction.

Ryobi:
18 Volt New - $100
18 Volt Reconditioned - $75
14.4 Volt New - $80
14.4 Volt Reconditioned - $60

The 14.4 volt appears to be the same housing as the 18 volt in the pictures. I haven't seen them in person. I wonder if they use the same gearbox. Anyway, not a whole lot cheaper than the parts to do a Dewalt, but with this you get batteries, chargers, and motors for other fun projects, not to mention a cool flashlight.

For the $20 range China drills, nearly all of them are one speed. But it was reduction I was looking for, not shifting capability. Now, what has our world come to http://www.homier.com/detail.asp?dpt=1&cat=12&sku=02642 The United States doesn't stand a chance. Americans might be out of jobs one day, but at least we'll have cheap tools.

EDIT2: $40 two speed http://www.homier.com/detail.asp?Ses...cat=&sku=04386

EDIT3: Okay now I just can't pick my jaw up off the floor I am ROFLing on. http://www.homier.com/detail.asp?Ses...cat=&sku=04039

EDIT: And while you're at it, pick up some Shazzam batteries! http://www.homier.com/detail.asp?Ses...cat=&sku=38612 I just can't some of this stuff. It's hilarious.