[EricH]

Cody, Art already pointed out a source--McMaster.

Also, if you have some idea of the diameter you want, please post that too. You gave us the length (>= 6"), but not the diameter. If diameter isn't a factor, then let us know. It's a lot easier to say, "Oh, we've got X bore Y throw" than it is to say, "Hey, got any 6"+ cylinders?"