Don, cant really say but I see a lot of them up here in Wa. Mostly hualing snow machines, but a guy down the road uses his for both. I would say talk to a snowmobile dealer to get some info and brochures, that will get you started anyway.
I have a '89 chev silverado and what I use to load my Sportsman 500 is a hinged ramp that replaced my tailgate, You may of seen something simular on landscaping trucks I can use it also to transfer my atv to other trucks and when the gate is locked I know my toy is safe.
Here's a link. I don't own one but thought about it..... www.saf-tload.com phone # 1-888-503-8855
I think their is a company in Colorado that builds them too. I think their are a couple of companies that build them. Good luck