Lol, they're not extra narrow...just 1/10th scale bore with wide-wound springs to prevent dirt from clogging up.
Thanks for the A123 suggestion though...I hadn't thought of them!
I'm not sure how well I'd be able to fit them on the chassis, as I'd prefer a 6 or 7S2P configuration which'd need quite a few cells. I'll have to look into that one, but it'd certainly be physically tougher than LiPo...*scrurries off to start measuring chassis space*