I have an '06 polaris sportsman 700 efi. It should pull it no problem, I've heard they're pretty easy to pull.
The disc is a kingkutter atv disc. it's only 33 inches wide which is what I wanted. I liked this crank up model better then the flip over ones because you don't have to unhook it and flip it over to transport it.
Here's a link:
http://www.kingkutter.com/WholeGood.asp?item=ATV%20Disc
It's $469 at fleet farm and $522 at tractor supply. i had tractor supply match fleet farm's price since they were closer to home.
As far as rocky soil goes- i'll tell you saturday. I'm spending all day tomorrow up at my land and will try it out for the first time. I can't wait to give it a try.