low aspect ratio wings and towing
So, yes, I believe it is possible to get an administrator waver to the operating limitations. I think Van might have done this on an RV-4.
But low aspect ratio wings make lousy tow planes. Because they have high induced drag, they need to fly fast. Setting aside the cooling question, which may also be a valid concern, you better plan on aerotowing at 90 kts.
Below 80 kts, the climb rate is going to be pretty poor.
I'm a glider pilot (LS-6) and a tow pilot. I think I'd rather be towed in a C-150 than an RV-8. (the c-150 with 150 hp STC is not a bad towplane, actually)