R/C car battery packs are effectively a wad of rechargable batteries soldered together. Since they're rechargables (often NiCad, NiMh and Li-on or Li-poly are showing up more often now too) the voltage is 1.2V per cell, so a 9.6 is eight cells. They'll usually be the same size as regular AA or C batts, but not always (some littler packs will be AAA or AAAA). Make sure you pay attention to the MAh (milli-amp-hour, mAh, mAH, I always screw that up) rating. The cheaper batt packs are around 1300 mAh, which is quite low. Better ones can be found around 2200 or 2500. They're designed to run hard for several minutes then dump their remaining charge fast. This works well for the style of motor used in R/C cars that suck up the juice fast and only need to run for so many laps in a race. The RQ should have a significantly lower current draw than your typical r/c car, so even a 1300mAh batt might provide decent run times.

The cheap packs can be found for around ten bucks, which isn't bad at all for six rechargeable C batts. You'll prob spend $35 to $50 on a decent charger. Not having a 'Quad I don't know the logistics of stuffing a 2x3 cell pack into the quad's belly, you may have to desolder the pack and reconfigure it's layout to fit properly.

In short, it's worth a shot. Let us know how you fare! 

Watch out, don't step in the anthropomorphization.