This is kind of a rare find, but I stumbled across a video featuring two straight male porn stars hooking up with eachother. They currently go by the names "Neeo" and "Cage" and are frequently on european porn sites such as Handsonhardcore.com, Ddfnetwork.com, etc...

http://www.tlavideo.com/raw-bi-bi-winter/p-217916-4

Anyone know of any other films like this?