He said he wanted something hard to tip over.........IMO .......stay away from theFull size Sportsman line-up...When he says utility I don't think he means a "work" Quad Just not a sport
I would say a 360 Kawi KVF(price range)or a Yamaha Bruin(size) or similar.................Caper.........

 

I would think a 400 HO would be ideal for what you have discribed...it is a bit more compact and sporty then a full size Sportsman, more then enough power with the 455 cc engine, over 100# lighter then a full size and you may be able to find a good used one for just a little over your price range...

Another option may be a Honda 420, they tend to be iron clad and the gear shifting tends to more then make up for an under powered motor! They do have a swing arm rear suspension, but if you are coming from a sport bike anyway this should'nt be a big deal for you! There should be a lot of used 420s out there also!