Powered Tow Bar

I did some searching but did not see any 'plans' or examples of a homebuilt battery powered tow bar...

I am thinking of something similar to the Sidewinder...

My current "long list of aircraft" are simply a Cessna Skycatcher and an Evektor SportStar ;)

Would one of these electric drills (18V or 20V) be practical for something in the 850 - 1000 lbs group?

And would figure on only needing 3 to 4 minutes battery life.
Of course looking for something light enough that won't throw my Take Off Gross Weight over the limits :(

Thoughts?

Ideas?