Glad I came back here to check things out (and look for Dave!). Since bigmac's post, there is actually a third book up which is located right here. It is a completely homebrew write up of the land south of Maztica known as Lopango. Its been given a Incan "flavor" based on what most have said about the land in the past.
There was a decent amount of material written on the tlincalli (scorpionfolk) of Maztica and their "retribution" on Amn for the plundering of Maztica. The next netbook, which is nearing completion, is completely focused on these creatures and many other authors have contributed to this ever-growing project. If you'd like to check out some discussion on the netbook's formation, you can find it on Candlekeep on this thread.
The next project after the scorpionfolk book will be a massive 3.5 overhaul to the campaign setting which will mostly be focused on the time period from Cordell's invasion all the way up to the Spellplague. Mr. Schwartz, what you've done here is amazing (just like the classes in Dragon) and I was wondering if it could be included in the project?
Either way, thanks for developing all this, it's such a shame that Maztica got dropped and then (literally) shunted out of existence! The "Maztica Alive! Yahoo Group" is located here if anyone else is interested in seeing what's going on.