The general rule is that extra attack abilities can be activated on any ability that can crit. This includes the proc on Drake Talon Cleaver and Hamstring. As I said, it's general, and I'm not entirely sure.
I've been seriously considering the epic PvP warrior gloves as the best PvE dps gloves in the game for Horde warriors - super cheap hamstrings will allow you to proc windfury repeatedly.
edit : There's lots of better weapons. Personally, I swapped to Skullforge Reaver when I got it, but that was probably a mistake. (It does, after all, have the single worst tanking proc in the game) Anything over 44 dps is probably better.
I've been seriously considering the epic PvP warrior gloves as the best PvE dps gloves in the game for Horde warriors - super cheap hamstrings will allow you to proc windfury repeatedly.
edit : There's lots of better weapons. Personally, I swapped to Skullforge Reaver when I got it, but that was probably a mistake. (It does, after all, have the single worst tanking proc in the game) Anything over 44 dps is probably better.
My other mount is a Spiderdrake