O.K., I've developed and printed a test roll. I used HP5, Rodinal 1:50, 70 F. and 5 inversions each 5 minutes for an hour.
I set up a little still life with various tones, etc, on an 18% grey card, then exposed as though the film was operating at 400-25000 in one stop intervals.
In printing (wet darkroom, Forte fiber paper, dektol, condenser enlarger) I found the "3200" frame to be just printable, though the tonal separation between the 18% grey card and true black was much smaller than normal. No surprise, but the "1600" negative prints quite normally and the "400" and "800" negs are just too contrasty to use.
I'd conclude that this is a good process for 1600 and wet darkroom work, but no more. Digital post processing could maybe be useful to 6400...
So is Tri-X very different? A couple years ago, I decided I was done with the stuff since I'd rather support a company committed to B+W and would like to be able to fix the purple all the way out of it...