I'm of the opinion just about any wood can be used for a neck... However, it's not just the species you need to be concerned with, it's the chunk of lumber itself. In other words, one piece of maple may be fine for a neck, yet another might not for numerous reasons, which I'm sure you're already familiar with.
Santos rosewood can make a very nice neck, however keep an eye out for signs of it twisting. I've used lots of it, and this particular wood can be very testy. It's a sin to toss big beautiful pieces into the burn pile, yet sometimes it's prudent.
I use pau ferro as the default fingerboard in a standard neck. People really like them and request PF over and over again.
-Doug