Yes and yes: this is an Italian threaded BB (and it's also Shimano, so it matches some of the other Japanese components)
and that's a Columbus steerer so it's almost certain to be Columbus tubing throughout.
Still doesn't answer the question of who built it, but the only thing that I've ever seen that mixes these Shimano bits with Columbus tubing has been the Bianchi/Puchs (well, and maybe a 3Rensho, but that's entirely another topic!). But I've never seen a CX bike labeled as Puch or Austro-Daimler, so it's only a weak guess.
Maybe you should start a new thread with "Austrian" or "Puch" in the title and see if it attracts the attention of some of the Austro-bike fans who post here...they might recognize something that I can't. Of course, it could just be an Italian make that I've never seen before (there must be hundreds) that sourced Shimano bits...a rare practice, but not unheard-of.
Last edited by unworthy1; 05-31-08 at 10:44 AM.