Here are the places that I know for a fact favor rotators:
NORTHWESTERN: They pre-screen you. If you don't have a chance to get in, you can't rotate. there are 9 spots and 8 are usually filled with rotators. About 50 interview for those 8 spots, do the math - best chance in the country to get in. that being said, if you screw up, you will not get an interview so you MUST be a strong rotator.
BOSTON UNIVERSITY: Has an application, but doesn't pre-screen. Rotating on the busy trauma service in the summer and kicking ass can make you shine. Getting along with the residents is key. You will learn a TON about trauma, which is bread and butter orthopaedics. 3/5 this year were people that rotated.
TUFTS: Will give an interview to ALL rotators. But beware, they LOVE the numbers. If you don't look good on paper, don't rotate. At least that's what the old chairman last year told me. They now have a new chairman, but assume that's still true. The class two years ago had 5/5 that were AOA.
One more thing of advice. If you are from the south for example and know you want to go to the northeast for residency, do one away there. You don't have to do it in the exact city you want to be in, but rotating far from home shows that you really want to be there and aren't just doing a shotgun approach to applying. Looking at an application from someone from the south, who has rotated at home, and in the west, they're less likely to take you because they think you're less likely to go there. Programs like to match people high on their list, just as you like to match high on your list.
That's all I know, hope this helps.