Fortunately, the integrated video on my Inspiron 530 can be, and has been, disabled. Also fortunately, the Dell position that the Inspiron 530 cannot support two video adapters is not quite true. I took the NVS 440 out of the R900 and put it in the x1 slot right beside my NVS 450. I won't be able to decommission my 530 but, at least once I move most everything over to the R900, I can downgrade my 530 by putting in a single 500GB drive in place of my 2TB [fake]RAID1, whose annoying behavior was the tipping point leading to my R900 purchase.
So, for now, my solution is to rack the R900 and forget about getting the add-in graphics working and use the multi-monitor support in RDP to connect from my 530. As more folks, with more patience and hardware aptitude than I, get R900's and turn them into workstations I may revisit putting a couple NVS 440's in it and decommissioning the 530. I'm sure I can't be the only IT person that works with a lot of test VM's and needs a workstation with lots of cores, lots of screen real estate and real [hardware] RAID.