My guess would be whatever a 100 series can tow x2 Jk.. We'll I would imagine the same as 100 series due to the fact they are close in construction. There are more variables that play in this also. You figure drivetrain wise you could pull whatever a 3/4ton truck would if you run the 6.0l due to they came in the trucks..
A stock 4L60e is rated at 13,500 lbs GCVW - so take the total loaded weight of the 80 and subtract that number from the trans rating to get the theoretical tow rating. Most will find that the remaining value is higher that the capacity of the factory receiver hitch. so basically the tow rating stays the same, but performance in improved significantly while towing. running a 4l80e would increase the trans rating, but the hitch (and potentially axles and brakes) would still be the rate limiting factor.