...on eBay 08/21/2014...
A 6 1/4" 30 cal bbl and an 8" 30 cal bbl...
But no threads and no front sight base...
I suppose if you're into sweating/soldering a front sight base on after cutting the thread, then these would be good deals...At a reasonable price...
http://www.ebay.com/itm/Luger-P-08-S...-/400755984567
http://www.ebay.com/itm/Luger-P-08-S...-/400755985122
Ignore the "Mauser" in the auction title; Numrich admits it is a mistake...
Kind of a strange way to make a replacement barrel...

If you're going to the trouble of turning the taper and the shoulder, and chambering it, but not machine the front sight base, why not thread it??? It doesn't matter where the barrel indexes, there's no front sight, no feed ramp, and no extractor cut...
Edit: I put a bid on the 6 1/4" bbl...Just for S&G...