The first is nysound.com. I have ordered several times from this company, and they are very reliable. In fact, this is where the cable set for one of the giveaways came from. Shipping is a bit steep, but google search for a discount code for free shipping - used to work, but I don't know anymore.

The second one to try for the latest eye candy is Catty (http://www.cattylink.com/engproducts.htm) I have never ordered from them, but I have asked for quotes and always received professional responses quickly. Again, I don't see any vacuum tube processors.

Best of luck, and if you find anything let us know......Colin