Largest I've ever smoked was a Room 101 Big Payback, a 7x70. It was a gift from my host at a herf, he handed them to us all at the beginning, so we all smoked them. It was not nearly as bad as I thought it would be, but I have no desire to smoke another one.

The longest I have resting is probably a Partagas Lusitanias (7.6"), the widest is probably a Behike 54, at 54rg (obviously). Nothing larger than that in my stock that I can think of.