The only truck bigger then the savage xl that I know of is possibly the CEN MT. That savage 5T is only available in Europe though you might be able to find the TVP's and shafts to convert your XL...
Dan4Lc on here sells the KM Baja 5T for a nice price. Hes still testing and posting his findings but it looks good so far.
As for the electric motors, with the new brushless motors there is no need for a 2 speed pinion. Plus with the reverse capability it wouldnt work anyway. I just picked up a Redcat Aftershock 8E with a brushless motor and the power is insane.