Billbillw thanks for the advice.
I read up on altitude mode last night before putting in the new bulb, as I figured that might include working the fans a little more.
I notice almost no difference in noise, and my adjustment to "ECO" mode has been minimal, since the bulb I replaced had been just about dead, so a new bulb in "ECO" looks almost blindingly bright. :-P
Cleaned the air filter (again, just for good measure), and it still was not dirty at all. I definitely think these bulbs have a serious heat problem. The dimming lamp that I pulled out had a bulb that was bent beyond a 45 degree angle and was turning a dark color.
Again, this happening at 1100 hours seems absurd to me.
Here's hoping ECO mode + altitude mode might help these bulbs live a little longer, otherwise I have to come up with a more costly solution in a year. :-(