Ilford Delta 3200 is too grainy with MF for you? Ah, well, that's a favorite for me. I've posted some really good results with it, and I like it a lot. (APUG link) I've seen a nice photograph enlarged to something like 30x40 or thereabouts. Enormous scene of a cowboy roping a horse in the snow, by Charles Guildner.
I have tried Tmax 400 at 1600 and 3200. I tried it with Xtol, but I'm going to do some testing with Diafine real soon. Tmax 400 is OK at 1600, but don't bother with 3200, as the shadows drop off from the midpoint.