you may not be able to get the new Tri-x in sheets, yet. I just bought 2 boxes of 5x7 and 1 of 8X10 from Calumet and it's still the old stuff. 35mm is now becoming available.
by the way "Photo Techniques" has a good article on the new kodak films in the March/April issue. Testing shows the new Tri-x to have finer grain than tmax 400.