I just replaced 10-1000watt MV for a customer of mine. Local supply house wanted $130 a bulb. "Hard to come by because they are becoming obsolete" was his remark. Found them on internet for $20 bucks a piece. Was also told by same supply house R30 75 watt bulbs(for recessed cans) were not going to be available much longer. 65 watt would be highest I could install. Who knows who to believe.
Personally, I wouldn't even think about using dilapidated technology like Mercury Vapour lighting anymore.
There are so many other better options available. The Colour-Rendering of MV lamps and thier relative in-efficency (compared to other light sources) pretty much rules them out in most applications these days.
Even the poor-man's street-lights use High Pressure Sodium or Metal Halide.
Let's face it, these days if you're not young, you're old - Red Green
I tried to find a replacement for a 100 watt mercury vapor. I needed an edison base lamp, but the supply house said it was obsolete, so I bought 2 150 watt HPS floods to replace them with. The others gave me problems all the time anyway... HPS seems the way to go anyway when trying to get lamp life hours. (24,000 hrs. lamp life) thanks for the input... Steve
I went looking for a replacement 70W MV ballast for an existing fixture and my lighting vendor said that a Metal Halide ballast will fire a MV lamp just fine, and that the only way he could get an MV ballast was to try and find old stock somewhere. I had to try it because there are another 15 fixtures, and swapping them all out for Metal Halide was not an option.
It actually worked very well, and has continued to work for several months.
Looks like, yes, MV are going the way of vinyl records.