Fallen, my man...I guess youve not seen this fisting-fetish sites? You can get pretty much ANYTHING in an ass..... I've seen two hands...baseball bats....size does not matter. Bigger size, just mean ya need more lube and more patience.
It's quite possible. I have a good friend that has always been more open and graphic about his sex life, among anyone he meets, than I would ever be. Anyhow, his wife had some colon problems before they married and he has expressed his disappointment to me about how there is no anal sex in his relationship.