Tom, This is my story.
I have a 61 inch SP61L2HXX Samsung rear projector. Beautiful picture etc etc and sound to boot.
I have had it 8 years or so now, and in that time has had three lamps... pick em up cheap now days.
Here is a TV I bought a few days ago (same model as mine)..... it was $20.00 :http://www.ebay.com.au/itm/261002167771?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648
I have thrown out the ballast board from mine 2 years ago, and replaced it with 2 x 40w ballasts from an old fluorescent light fixture (the iron choke type) Used the neon from the starter and a capacitor, and that provides the start voltage for the hid lamp (6000v or so), so that bought the power down from 120W TO 80W just for the lighting part.
The logic and LCD driver uses very small power, about 15w, and the audio down low is about 5w.
So now the TV runs all night every night (and I mean all night no exceptions from the boss) for the last 8 years and will do for the next 8 years.
I bought the one shown above for parts for the main board (computer logic) and lcd generator..... so that if anything goes wrong with the color generator or main board then we'll be ok for a long time to come.
Total power seems to come in around the 100w mark, so it uses 1.2kwh per night. I have to live with that.... no question.
So, the next step is looking at a 50w HID car globe and ballast, and setting that in an old globe body (for the focal length), and see if I can get almost the same pictures with half of the original power. I think so, but don't know so as yet.
Rear projectors seem to have the most problems in the power board, and the ballast board.
As of now the power board does not provide any power to the globe (now it is direct mains relay ......switchable from the mother board), it is doing it easy, and the ballast board is in the rubbish bin. .... it should last almost indefinitely now as the computer part stays cool, and it has less mysterious parts to blow up..... and spares are very cheap and plentiful for now. I see another one (tv) on ebay for 99c, so may buy that as well for parts, and that should be it.
It cost near $9000 in it's day, but if I keep it going for another decade or so, it will amortise out ok.
At least I have some control of how it works and how hard it works..... try that on an LCD or Plasma etc.
Have fun with it anyway.
Edit There is a down side to the modifications with the flouro ballast. On a cold start the 6000v start pulses are enough to start instantly, but if the thing is turned off and straight back on, it will not light the screen for 5 mins as the gas cools. The original ballast provided 28000v for start function...... but this one does not get turned off and on anyway.