Just got my approval letter the other day. I did an ACGME Transitional Year at a hospital that also has an AOA Traditional Rotating Internship and prior grads have gotten approval. That probably helped, and both interns have the same rotations, except electives of course which vary. I had to do a little more crap during internship that my MD counterparts didn't have to do. I had to keep patient logs, reading logs, conference/workshop logs, etc. Also had to meet with the AOA DME and my own program director quarterly. I couldn't make it to the AOA conference in Orlando last year so I went to the California DO society annual meeting, OPSC. My reasons for getting it approved were combo of geographical, personal and radiology residencies on the west coast, and one of my rads programs I applied to had a linked internship and if I had matched to a DO internship, I would have been dropped from any chances at that program. As competitive as radiology is, I didn't want to risk it. I sent copies of my NRMP rank list as proof (so you may want to print that stuff) and my program had to send a letter that stated what rotations I did, etc. You can do most of this stuff early on, especially writing your statement on why you had "exceptional circumstances" that necessitated you doing an ACGME internship, and send it to the AOA early. And then at the end of internship, you can send a letter or copy of your diploma saying that you successfully completed the internship and that's it.
In my case it was a matter of more paperwork and hassle, but I figured what the heck, who knows where I'll end up. I honestly don't see myself practicing in any of the 5 states, but should I have personal reasons to leave private practice radiology, i.e. ill family members, moving, who knows, I might have a better option of teleradiology, because some teleradiology companies might want me to be licensed in one of those states.
Hope this helps.
Vince