Hi jfnatx,
sorry but i haven't been reading these forums often and missed your post. Likely you have already sorted out your PCIe graphics car 
What i can say is that T610 and T710 are similar in many respects but unlike the T610, which does not have a x16 PCIe slot, the T710 is blessed with a x16PCIe slot. On-board graphics can be disabled via BIOS but you need a graphics card inserted into the PCIe slot to allow this option to be changed. This should make using a PCIe graphics card on a T710 a trivial task.
What this means in practice is that the x16 slot may not be able to provide a full 75W via the PCIe slot itself, so you are then limited as to what graphics card you can use. If you stay within power constraints that Dell recommend, that is 25W for the T610 (you should check your Hardware Owners Manual for your teh T710 expansion card power limits) them you should have no issues. The reality is that any modern x16 PCIe graphics card within a 20W -30W maximum power limit should be OK to use.
Just don't go crazy with a high end card unless you are keen to modify cards and/or connectors and don't expect to be able to use crossfire/sli (though i suspect multiple low power firepro/quadro cards may work). Oh, and don't expect Dell to provide support for graphics issues AND don't expect the unit to be quiet [:?]
Like anything in life caveat emptor...