We are hauling a 2005 Montana 3400RL which has a "posted" GVWR of 13, 975 lbs and a stated pin weight (when the coach is empty except for standard equipment) of 1,975 lbs. Our tow vehicle is a 2005 Dodge 3500 Quad Cab 4X4 with the Cummins Diesel, auto transmission, single rear wheels, the short (6.25') bed, and 3.73 gears in the rear end.
The Dodge itself has a GVWR of 9,990 lbs (effectively 5 tons) and a towing capacity of 13, 950 lbs. The vehicle weight including me, a full load of diesel fuel, and the hitch is approximately 7, 680 lbs. With a more realistic hitch weight of at least 2,100 lbs, I am up to 9,780 lbs. That leaves 210 lbs for my wife and any other cargo we want to carry in the truck.
The message is that a Dodge 3500 (as ours is configured) is very close to being "maxed out" in terms of both towing capacity and weight-carrying capacity. In truth, we are likely over weight.
The two Montana models that come closest to your stated preference for a 32-footer are the 2955RL and the 2980RL. The 2955RL is well within the towing capacity and weight carrying capacity of the Dodge 3500. It is also within the capacity of the Dodge 2500 (but the difference in cost is only about $400) ... so my advice is to go bigger.
The GVWR of the 2980RL is slightly higher than the 2955 RL (still well within the towing capacity of the 2500) BUT the hitch weight is significantly higher ... higher than the 2955RL and the 3400RL. That fact also suggests that a 3500 (one-ton) pick-up is the wiser option.
All that having been said, many folks haul 2955RLs, 2980RLs, and 3400RLs with 2500 (3/4 ton) pick-ups and seem to have no significant problems. Many with whom I am familiar install air bags or some other device to increase the carrying capacity of the pick-up ... but the new diesel engines that reside in the Dodge, GM products, and Fords are all beasts and have plenty of power to haul the weight.
With regard to the short bed, we have an automatic sliding hitch (PullRite Super Glide) It became evident very early on that a sliding hitch was necessary with the Montana and the short bed in the Dodge. In a tight turn (almost always backing up) there was a very real risk of a collision between the front cap of the coach and the rear of the quad cab. Our first hitch was a manual slider which we found to be annoying and a pain to operate. As a result, we bit the financial bullet and installed the automatic slider. We no longer worry about the problem. If you buy the long bed (8') dually, no problems. No slider hitch is necessary.
It has been reported (allegedly according to the PullRite people) that different brands of trucks have different dimensions in their short bed models. While all short beds are 6.25 feet, the critical dimension is the distance between the center of the rear axle (where the hitch is mounted) and the rear of the cab. Obviously, the greater the distance, the less one has to worry about clearance problems. The information I have seen suggests that GM short beds have the greatest distance (clearance), Fords are next in line, and Dodges have the shortest distance (least clearance).
As you are also likely aware, the 2006 Montanas have a new front cap design that is supposed to reduce (or eliminate) the clearance problems for short bed pick-ups ... and the need for a slider hitch. I would certainly investigate whether that is indeed the case with whatever truck you wish to buy ... but I would NOT recommend that you simply assume that there are no clearance problems.
On balance, I am a big advocate for getting the biggest truck you can afford ... a 3500 if possible ... and diesel powered. I also encourage you to join the Montana Owners Club Forum
http://montanaadministrator.forumco.com/default.asp
It is a great forum, very friendly, and loaded with information, good and bad, about Montanas. Any questions you may have will be answered there.
I cannot comment on the other RV brand that you mentioned ... but hope this is somewhat helpful re Montanas.
Bill