I am sorry to hear of the problems you are having, and I feel for you...
I am a TV tech, and in my opinion, All of the Mitsubishi V26 Chassis based sets (WD-X2X2X SERIES) are - JUNK - LEMONS. I really LOVE Mitsubishi, but this series of sets should have never reached the retail shelves.
Just to let you know and make you feel maybe a bit better, I have a TERMINALLY DEAD WD-52525 about 15 feet from me as I type this..
Unfortunately this is a very common problem/repair on these sets. However, being a common repair doesnt make it easy, or cheap.
The problem with this line of sets is the sub-standard JAMICO branded capacitors that mitsubishi used in this set on ALL the boards.They are not a high enough temp rating, and they will eventually go out of tolerance and make strange things happen with the set (it sounds like yours is on the way..) , eventually ending in the green "blinking light of death" --(the set will do nothing other than flash the green LED forever)
The Power supplies, Format, DM module, signal and terminal boards ALL will develop bad capacitors. They CAN be replaced with new ones, but this repair typically brings a cost of about 700 dollars or more if you have it done at a shop.
Its really more of a gamble fixing this set, because they also have their share of problems with the light engines as well. (developing hazy pic, splotches, etc etc..) However....If you can get the set repaired for a reasonable price you could sell it... or it may last a few more years - but this is where you have to ask yourself if the 700 dollars would be better put towards a new set. (I honestly think it would be)
I have heard rumors of a class-action suit against Mitsubishi for the entire V26 chassis series of tv's but nothing is set in stone yet. You may want to google Mitsubishi DLP lawsuits.
I would honestly take the 850 and go get yourself a 52" LCD tv -it will cost more than 850, but it would be....Wise..
IF you choose to go with an LCD TV, I will do you a favor as well, and warn you - STAY AWAY from the cheapie brands such as Olevia, Insignia, Polaroid, and Vizio - be wary of Phillips/Magnavox - they arent what they used to be.
When it comes to LCD tv's the saying "you get what you pay for" definately applies... Get a known brand, such as Sony, Sanyo, Toshiba, LG, Pioneer etc etc... Also, I am normally one to completely discount extended warranties, but I would highly suggest one on the new LCD TV, as they do generate alot of heat, and heat IS the enemy of electronics..
I wish I could have given you a more "optimistic" answer, but you asked for my opinion..LOL Have a great day, and I hope I have addressed all of your concerns! If you need anything else, Just reply!
Have a Great Day!