Hi Maverick,
This is late, but I can confirm the original Rainbow Six, Rogue Spear, Urban Opertions and Black Thorn all work on Win7 Ultimate x64. Please note that I use the updated versions of RS6 and RS from Tom Clancy's Counterterrorism Pack - which was re-made to work on XP.
The original RS6 kinda works -- it runs really fast =/, and for me it has this bug where if you save too many plans for one mission, waypoints start disappearing or the mission will crash.
I'll post my compatibility, graphics settings and a handy tool to stop the engine from "shimmering" when i get home. P.S. Rogue Spear does *not* like to be run at a refresh rate greater than 60mhz!