Here for your enjoyment is the "TechTube" site. This is the remains of the former Blackburn Mullard factory and what they are doing today. They cannot use the Mullard name anymore (owned by New Sensor).
The nice thing about it is knowing that there is yet one more source for a "real" tube. I do not know who distributes them here in the US. If you find out, let me know. They are currently making 12AX7's, 12AU7's and 12AT7's. All premium high quality for audiophile use (my Marshall qualifies as an audiophile amp).
Oh yeah...the video of how they made tubes is on this site as well.
TechTube Valves - Blackburn MicroTech Solutions
Marty