Line Magnetic 508ia and the Elusive 805 Tube

Greetings, my fellow 'Goners.

I'm the very happy owner of a Line Magnetic 508ia integrated amp, a real powerhouse with a wonderful sound. I have replaced all of the stock tubes except the 805 tubes, as the stock tubes have suited me just fine. However, after a year or so of stellar play, one of them is showing signs of not being able to hold bias, so it may be time to experiment with some other tubes. Fine, but when I began looking around, I discovered that 805 tubes are not exactly plentiful across the land, nor is there much conversation about them. I found some on eBay--the Fullmusic look interesting, but pricey. My usual sources for tubes have none at all in stock.

So my questions are whether anyone out there with an LM 508 has tried rolling the 805 tube, what were your results, and--most importantly--where did you track them down?

I was very pleased with the results of rolling the 300B, 6SN7, and 6SL7 tubes, but the 805 options are relatively limited. Any insights, links, etc., would be most appreciated.