When I use Tri-X in the Lynx 14 (max ISO 800, max SS 1/500), I develop in Diafine, which bumps the speed rating for Tri-X to 1600. I expose at 800 (max I can set the camera to) and, while I get very good negatives, they're a bit dense but I like the look.
Really, while high-speed film has improved, my experience at least with the type of shooting I do, hand-held candids... I've realized that you really don't need high speed film with a fast lens. I would rather shoot 400 speed with the f1.4 on my Lynx. 800 is fine, and really beynond that (shriek) you need a flash. It's easy to get enamored with high film speed ratings, but in "available darkness" often you ask the camera and film to do the impossible, and the results disappoint.
I came to this conclusion, and felt vindicated when a book on low light photography echoed this... Go with lens-speed over film speed, and really an 800 speed is plenty. The only time I use 1000+ film ratins is when shooting available light with slower medium format lenses to compensate for the slower lens.