Anyone know of any small (2A-5A) RC speed controllers that can be run from a nominal voltage of 3.6V? And that aren't too expensive?

I've made two 3.6V battery packs up from an old 7.2V Nicad pack I had lying around to provide power for a kilobot because a) they weren't really doing anything and b) I've already got chargers for them so it would save me having to buy new gear. The only problem is that most speed controllers have a low-end voltage input of 4.8V minimum. There are some speed controllers on Technobots that run lower than 4.8V (some of the Pololu range) but they're designed for logic input and I don't know if/how they can be modified to take an RC input. If I can't find anything I'm considering resorting to small-scale servo switch units.

As for the kilobot itself, I've postponed the crusher design for now as it was going to be too costly for a first attempt so I've decided to go simple-ish and classic with the design. Recognisable classic actually, in the form of a Cassius II replica (minus active spike). Pretty much settled on drive motors, wheels, battery, weapon power (a bad-ass 20kg/cm servo weighing in at 160g :twisted: ) and chassis shape/materials. Going to make a cardboard cutout and try the parts out for size in that first. If I opt for the servo-switch method, I'm looking at a total cost of £45-£50 which is pretty win for something which, on paper, should be moderately decent. And if it gets smashed up, then it won't have been too much of a costly endeavour (in keeping with the original robot design, the armour will most likely be polycarb)