Sulfur Lamps?

About two or three years ago there was a big stir about sulfur lamps. These lamps where supposed to use six times less energy than metal halide or high pressure sodium lighting. Also, they spectrum of light the gave off was nearly identical to that of the sun and were expected to never burn out.
The early articles said they had put some of the lamps in one of the Smithsonian museums and were getting rave reviews and saving money on energy bills to boot.

And then … nothing, nada, zip, zilch. I haven’t heard a word about them in the past two years and I can’t find a single company on the web that sells them.

So what’s the deal? Is the technology not refined enough yet? Too expensive to implement that it would negate the energy savings?

Or could it be something more sinister? Perhaps the technology was quashed because the lamps would make it more difficult to detect large-scale marijuana growrooms because of the low energy usage? Just a theory, but I wouldn’t be surprised if it’s true.

Anyone know the real reason why sulfur lamps aren’t in every street light, sporting arena, and department store?

Here is a site of one of the producers of sulfur lamps.
http://www.pge.com/customer_services/business/energy/smart/html/sulfur_lamp.html

By my reading it looks as if it is currently best fitted to large spaces needing large amounts of light. In these instances it will save money over a period of 10 years, if I read it correctly. It sounds as if they are trying to develop this for smaller outputs but that they still have a way to go yet.

My apologies on the girth of my post.