I would say your best bet is C&J in NYC since they get them directly. However, it seems that all of Jimmy B's shoes from the last movie are in high demand. I have to say I do find this trend interesting since I've had my pair for a number of years (including the Alex).
Ironically I've always wanted the Tetbury (even prior to the movie) because it looks like a great rainy day boot for the fall.
Thanks. I guess I'll give them a call. I'm pretty new to all of this stuff. I've looked through several similar boots to the Islay, but for some reason, it stands out. I'm still learning, but thanks for the advice.