Thanks for the bump. I think I'll try this stuff by dropping the blower assembly.
http://www.autoacsystems.com/_store/storeopen_odor.html
Based on reading this thread, could I spray through the driver foot vent and also get to the evaporator? Is there an ideal place to drill a cleaning hole for access? If you vacuum first as suggested in an old post by connecting a shop vac to the center vent, wouldn't that be trying to pull the crud through the evaporator? Wouldn't it be better to put the shop vac in the channel going from the blower to the evaporator and try to suck it out in reverse flow?