I will be shadowing a D.O. at his practice next week. If you need to find a D.O. in your area you should go to the AOA website. They have a search where I think you can even enter the specialty you are looking for. Good Luck
I start shadowing a D.O. today and she is in private practice. I found that the D.O.s in my area that were in private practice were more willing to have students shadow them then the D.O.s in the hospitals.
It is generally true that DOs in private practice have less red tape (ie HIPPA) to deal with than those in a hospital setting. I ended up shadowing a DO in a private practice after several (failed) attempts to shadow hospital/er docs.