First find out what your Vehicle is rated to tow. Check your owners manual, tow ratings should be listed in it. Does it have the factory installed tow package? A factory installed tow package on a mini-van will almost double its tow rating. Without a factory installed tow package on a mini-van you are limited to some of the smallest pop-up with loaded weights under 1500-2000lbs. With a tow package you can sometimes goes as high as 3500lbs.
A hybrid camper is a Harded Sided Travel trailer that instead of having beds on the inside has bunks that are similar to a Popups that are coverd with canvas and fold down from the front and back. They make for a lot of trailer in a much smaller package. A min-van with a factory installed tow package, might be able to tow the smallest of these with lenghts of 17 and 19ft and total packed weights in the 3000-3500lbs range. I say might, because the front wheel drive and Uni-body construction of most of today's mini-Vans make them poor tow vehicles even when towing just a pop-up. I towed a 1500lbs '88 starcraft for 2 years with a Ford Windstar with no tow package. It was doable, but I much preferred towing it with my Mercury Moutaineer.
The best thing to do when looking for a new camper is to hit some camper shows. Unfortunatley they are generally in January, Febuary and March and are now over. Buying at a show may or may not be your best bet(Show prices are NOT always the cheapest price you can get, I know this for a fact from just purchasing a new TT. Ask me and I'll go into details), but for variety of campers on one place nothing beats a camper show.
Also do check out some of the forums listed above. I'll second Pop-UP times as being a great site pre-subscription. I have shifted my focus to Travel Trailer info so I'm not sure which is the best non-pay site any more. Also RV.NET and IRV2.com are great sites for Travel Trailer and Hybrid info, and more limited pop-up info. There is a Yahoo site that is dedicated to Hybrids, but I don't have the address with me at work. I'll try to remember to post it when I get home tonight.