There are different sizes but something like this would fit at least six 6" deep full sized pans in it. We have put meat, cheesy potato's and green beans for 200 people in one before. I would suggest stacking them on the floor (and on top of one another) and not using the racks if it is a really heavy load as you can bend the brackets bouncing them down the road. I'm talking 2 30+ pound pans on each level though.
I've done a load test on mine and they pull between 850 and 1000 watts. The bigger one has a small convection fan that runs all the time.
I would suggest getting one with a mechanical thermostat rather than a solid state thermostat. They are cheaper to replace if you ever have to do that.
Decent sized rollers on the bottom and the side handles are really nice to have.
http://www.ebay.com/itm/Cres-C...&hash=item35e525b1ed