I tried posting this news to textbook-l, but it seems that subscription rates on that list are very low lately.
I received an email today from Frederick Noronha, a person who helped with the UNDP-APDIP book donation from two years ago. He is helping to set up another book donation from APC.org. I don't have any details about it yet, but it's something to look forward to. As we gain more credibility and more acceptance, I think that more and more organizations are going to turn to Wikibooks to host and develop free books. This kind of publicity is, I think, a good thing.
I'll post more details as I learn them myself.