Larryi,
sadly its a sign that this technology has become a bit of a dinosaur with only the select few interested. Although I see a few tube docking stations for ipods!
I know many here will disagree here, but in my experience other technologies, especially in power amplifiers, have moved so far ahead in terms of what you get for your money vs performance, and without the insecurities of knowing whether you have the best tubes from the 1950s or not.
The small magical details that we obsess over like this tube or that NOS tube bringing out extra detail here or there, can be had at the flick of a button on a remote control now without even reaching for a screw driver.
I have been trying out some of these latest generation of digital and switching amps for a while now. Some amps have room correction and a host of toys built in. The various filter settings are very powerful and have similar effects to tube rolling.