Would this esc be suitable? Mtroniks MicroVIPER Marine10?
http://www.mtroniks.net/mtroniks_SC_...ubCategoryID=3
The size would be ideal at a petite L26.0mm x W25.6.0mm x H9.0mm, even at that size it'll only have a couple of mm to spare between the driving wheels!
I can fit a 5 cell humpback AA battery pack under the bonnet and with the 2 cells on one side and three on the other it even just clears the cutaway in the bonnet for the air filter
