Any integrated using 6550 tubes...

Passion Audio I-12 uses 6550's and comes assembled or as a kit. They are "said" to be slightly upgraded Antique Sound Labs amps, though the upgrades may be mostly cosmetic.

The big hottie here is the cary SLI-80 Signature. Hnads down nothing has come closes here. I have a customer who lurks here that bought an SLI-50, which he loved so much he then got the 80. The SLI-80 Signature is a very flexible amp that is switchable on the fly from 40 watts triode to 80 watts ultralinear. Two ways to run the tubes. Tube headphone amp. Remote. Tube rectifiers. And runs thre tubes easy..so it's a no-brainer to live with. And it is so musical. A couple folks have reviewed it at www.audioreview.com You can see better pics on our website

If you don't like the sound of the Svetlana 6550s that ARC ships, you can get some KT88s, KT90s or if you can afford it tung-sol 6550s from Upscale Audio