Countryboy,
The RTV's are great, but as you mention, they are more work machines than play. I have a Gator HPX. I got it before the new XUV series, but they XUV's are awesome. I plow through the winter with my Gator, plowed up to 3 feet in one snow fall, works amazing. I bought the blade expecting it to just shorten the time for some light snowfalls but it really has replaced the need for the tractor in the winter, and is much faster. I still plow with the tractor occasionally, but just to keep it running.
As far as the belt goes - no problems. I've had 3 gators, a 6x4 - which was clunky and slow, to big to maneuver, so I got the 4x2 - still slow but maneuvered a lot better, then wanting more speed got the HPX, now I find myself wanting an XUV:licking:, but that'll have to wait as I just bought a new tractor. On the couple thousand hours between the 3 gators, no belt transmission problems. I really think people make a bigger deal out of it than it is. The HST in the Kubota's is nice, but I really don't see the belt drive as that much of a disadvantage.
I think you should look at the 825i. I believe it does 44MPH, and a high performance automotive style gas engine. If you really want diesel the 850D is a good choice as well. My HPX doesn't offer a bench seat, but the new XUV's do have a bench option. The XUV does off a cab, not on the same automotive feel on the inside, but at least keeps you protected.
I really don't think you can go wrong with either. RTV is a little more work where the XUV is a mix. I can tell you after all the work I've put my Gators through though, they are excellent work machines. Really depends on what you need.
For reference, below is my HPX, have a homemade cab, front blade and hydraulic dump bed.