Bill/Diana,
I have never seen a minivan being towed by a gas MH. The minivan is going to exceed the MH capabilities.
Our minivan doesn't. :) It weighs in at 4,460 lbs., fully loaded it and our rig weigh in around 25,500-25,900, under the 26,000 lb. GCWR. Also under all axle weight limits and GVWR.
To the OP, I wouldn't worry about the toad now. You've got a couple of years before you will need one. By then, there may be vehicles available that's aren't now, and vehicles that can be towed now may not be towable in future model years.
If you need a minivan, however, I can highly recommend a 2004 and earlier Honda Odyssey Minivan. Flat towable, lots of space and if you get the right gasser, you can stay within weight limits.
~Rick
