UPDATE: It worked!
All I had to do was tell the onboard GPU to stay on all the time in the BIOS, load up the drivers, hook up the displays, and go into the display properties of Windows to set them up and expand them correctly all together (Nvidia and Intel's control panels would only allow you to control the two displays hooked up to them obviously). I have 2 monitors hooked up through DVI on the 8800GT, 1 monitor on the onboard DVI, and 1 monitor on the onboard HDMI w/ an HDMI-->DVI cable, with one primary and 3 expanded setup in a 4-monitor square (still need to mount them though). Works great!
Just thought I'd post the results for anyone else looking to do this in the future.