My Alexander 164 5V BBb kaiser tuba is for sale at Noah's Brass Ark in southern California http://www.brassark.com/sale/
It is priced at $7800 which is as low as I can go. I will be taking some other horn to Noah's shop in the near future and if it hasn't sold by then it will be coming back home with me.
It is only for sale because I learned tuba on CC and haven't wanted to divide my practice time to learn a new set of fingerings (I also play horn and contrabass clarinet so my practice time already gets divided). Some of you may remember that the Horn Guys had a CC 164 a while ago - I almost bought that one except it had some unworkable pitch issues for me. The BBb version has no such problems.
This instrument was built to order in 2008 and has had very little playing time. The 5th valve is convertible between a conventional 2-3 combination or a very useful tritone (in-tune 2-4). To the best of my knowledge nobody stocks these horns in the US - they are all built to order, so a pre-owned horn is the only way you can play one before committing to purchase. Forget all the discussions about "core" - this horn defines the term as far as I'm concerned. A winter hard case (with wheels) is included.