So i can take an RB750, run a wan connection into port 1, run a hotspot off of port 2 (with its own DHCP server) and a totally separate network (with another DHCP server) off ports 3, 4, and 5?
Yes.
http://wiki.mikrotik.com/wiki/How_to_configure_a_home_router
That final config more or less applies to what you’re doing - just instead of using one interface for a DMZ you’ll be using it for a Hotspot.
So there was a trick to accomplishing what I wanted… I had to set the “master” to none on the ports I wanted to setup with a different ip / dhcpd server etc. now that I have figured that out I love these things!