Al -
You're right - some vehicles won't/can't accept a weight-distributing hitch. This is due to the vehicle construction, rather than a problem of the manufacturer not making a WDH available. We've had quite a bit of discussion about it on this board. A search using the keyword "unibody" or the keyword "frame" ought to bring up a lot of it.
I can't speak to your Volvo specifically, but according to the Draw-Tite web site (a major hitch manufacturer):
"Class I hitches are weight carrying (WC) hitches rated up to 2000 lbs. gross trailer weight (GTW) with a maximum trailer tongue weight (TW) of 200 lbs. A Class I hitch usually has a 1-1/4" square receiver opening."
If you find that are towing a 2720SL with a Class I hitch, you may find yourself in serious trouble.
Draw-Tite will sell you an aftermarket Class II receiver, rated for 3500 pounds trailer weight and 300 pounds tongue weight (no, not 350 pounds). Sadly, the tongue weight of a 2720SL, loaded and ready for the road, is quite a bit more than 300 pounds. You really should weigh your TM. My 2720SL runs 550 pounds of tongue weight - I posted the specifics here.
http://www.trailmanorowners.com/foru...ead.php?t=3144
Regarding your specific vehicle, was your hitch an aftermarket unit, or a Volvo OEM product? If it came from the Volvo factory, what does your owner's manual say about the hitch ratings?
Bill