 EUREKA  BAM! Got the parts List The 7HMHP is the Card. That doesn't cover the GPIO and Display port cables however. These are NOT optional. There are 2 Kits I have Identified. 540-BBJC    UK version 540-BBIO     USA version Interface cards/adapters Thunderbolt PCIe card for DELL Precision 1700, 5810   GGTXK  is the Display port wrap thru cable. [IMAGE] NK4P3 is the GPIO cable to the motherboard. [URL]    [IMAGE] [IMAGE] [IMAGE] [IMAGE]
I see this article regarding "thunderbolt add in card" for T7810... <ADMIN NOTE: Broken link has been removed from this post by Dell>  Where can I get the card? Looked everywhere, can't seem to find one.. Maybe one for an HP is the same? Thanks!  
Thunderbolt add in card.