Theres a guy on ebay who regularily sells 9mm barrel blanks. I'm not sure at what point the US requires export permits, as at the point of being a blank, it isn't really a barrel yet. He charges something like $20 for them. I believe they were 20" long.
I had a barrel maker from Alberta make me up a blank for a 9mm, but he broached it as a .357. Wasn't cheap though, between $200-300.