Pat, Briley or Kolar will make a "carrier" barrel out of any length barrel you send them. Just send them the barrel, tell them what you want the finished product to weigh with tubes and presto...I don't think Krieghoff ever made any carrier barrels longer than 30" since they were marketing to skeet shooters.
I have 34" LW Sporting barrels that weigh 1.664kg and would like something closer in length to my 12 ga barrels when I shoot sub-gauge.
Thanks for the responses.