Apologies if this is old news on the forum.
The bulb in my 2005 56MX195 blew in February, after a couple months of use, so I called Toshiba for a replacement and they shipped it to me. Today, I finally got around to calling FedEx to get them to pick up the old bulb.
Anyway, I just got a letter dated March 23 from Toshiba. It says my TV is in the 2005 group with a bulb problem, and they've already replaced the bulb once, but they'll be sending me a new and improved bulb no later than May 31, 2006.
On the replacement lamp, they say "In the time since you received your replacement lamp, Toshiba has been advised by the lamp manufacturer that a new and improved lamp will soon be available. Our expectation is that the new and improved lamp will help optimize lamp life and performance."