Hey guys, this is Carlos Montero, Project Leader for Black Mesa.
I don't come around here often, but I wanted to say thanks for the support and honesty. Lot's of people I've looked up to in this thread, and it's great to see people enjoying the game after all we've put into it.
Thanks again! 
Sorry to burst your bubble, but Portal 2 being released in April does not automatically imply that we will get an SDK update in April.
This is a pretty neat idea. Despite the obvious heavy workload overhead, it could lead to really great results if it worked. That being said, I don't think that the MDL format supports a 2nd UV channel at all. I'd imagine that kind of feature is not possible to add without Valve's help, as it would involve changing the model compiler itself.
