A good butcher should be able to assemble one for you. We had one put together by a meat shop in Cincinnati for a holiday meal a few years ago.
Now that is something I'd really like to see. It's not so much the stuffing one bird into the other so much as I'd like to see how they debone the entire bird. (Assuming Steven hasn't covered this in one of his many great books...)
Come to think of it I'd also like to see how they prepare the 6-legged turkey as well. That is, unless they just use farm-grown 6-legged mutant turkeys, because that wouldn't be much to learn at all (that's legal anyway).