I'm still hoping they come out with some sort of service to convert your gas vehicle to an electric one. I'd like to try offroading without having a torque converter.
I don't know how practical it would be to convert an ICE (internal combustion engine) vehicle to electric. It would be very expensive and much of the design of the ICE vehicle is to accommodate the various ICE components that wouldn't be needed on an electric.
My guess is that the first electric off-road vehicle will be a 4 wheeler of some type, possibly similar to a Razr or other side-by-side. I could also see a dedicated rock-crawling electric built on a tube chassis with 35"+ tires and electric motors on each wheel. That would eliminate the need for CV joints and allow maximum articulation on a 4 wheel independent supension, since all you would have to have is a sturdy wire going to each wheel-mounted electric motor. Mount the batteries low in the chassis since they are so heavy and it should have a low COG. Put a battery charger on the trailer and then tow it to your favorite 'wheeling spot, rock crawl all day and then drive it back home on the trailer.
For highway-bound vehicles I think we are stuck with Hybrids for the time being, simply because carrying enough batteries to give a vehicle sufficient range is going to be problematic, and recharging time is crazy.
But an all-electric hybrid system (that is, a system where the ICE engine is never actually connected to the drivetrain) would eliminate the need for a transmission, CV joints, driveshafts and axles.
Basically you could have a similar arrangement with electric motors on each wheel, an ICE engine with a gas tank to charge the batteries and a bank of batteries underneath. The ICE engine would run on gasoline (or whatever) and charge the batteries while the electric motors do all the work. If you have a sophisticated enough computer, the fact that you have 4 separate motors can give you 4 wheel drive, 2 wheel drive, and full traction control. It could also use regenerative braking to help charge the battery and on long drives, the engine would shut off once the batteries were charged and would not start up again until the batteries hit a certain threshold.