So part IV isn't available for nook through their store. The other ones have been. Do you know what the deal is? I want to reaaaaad.

Hi, 

I have submitted it to B&N, but sometimes it takes a few weeks to get there. It is at Smashwords. Their EPub format is what Nooks read. 

I’m really sorry I can’t hurry the process up for you!

Here are the links again: 

Amazon U.S., Amazon U.K., Amazon DE, Amazon CA
Got a Nook, Sony Reader, or Apple device? Get it at Smashwords