In previous years some press photographer used HC110 replenisher to develop Tri-X to speeds around 5000-6400. The HC110 replenisher is no longer available but I've been meaning to try the LC110 from Freestyle (and then, if that works, try it on TMZ and Delta 3200 ) I have the info on that if you want it but you need faster.
A while back I stumbled on this recipe for something called "Super Soup" :
I've been meaning to try this too, but it's clearly more complicated than just diluting some HC110 or LC110 replensiher and using it to develop. So just now I googled for that Super Soup recipe (I had the info saved as a text file but wanted to link to the original author) and found this on Digital Truth, involving developing in Diafine followed by Rodinal 1+100 stand, followed by Super Soup:
This looks fascinating in a "try it and see what it does" kind of way. I seem to frequently find myself shooting black cats on coal piles at midnight (well, metaphorically) so I used to always be looking for more effective speed. Since the advent of TMZ and Delta 3200 that need is greatly diminished as I can go to 6400 with quite acceptable results with TMZ and to 3200 (to be fair, I've not tried 6400) with Delta 3200. But of course that does no good when you've already accidentally shot at that speed on Tri-X.
Let us know what approach you settle on and how it works out. I'd love to hear about it, especially if you get decent results.