Jorgen,
Ilford Ilfotec-HC is almost the same, and Legacy Pro make L-110 which is said to be the same but without the thickening to make the concentrate into a syrup.
I have developed XP2 in Rodinal 1+100 for one hour, with six inversions at the start and again at 30 minutes. Expose at EI 200 for best results, and it will be sharp and smooth.
I've used Diafine, but the result is too grainy in 35mm, but tolerable in 120. 3+3 minutes will do it.
When I was mixing up Quall's monobath I tried it in there but it's a bit gritty and there's no advantage in XP2 over, say, HP5 if you're getting gritty pictures.
Apart from the 1 stop pull for the Rodinal semi-stand, I haven't tried any other developers at other speeds except for the HC-110. I'm amazed at the smoothness in a film pushed three stops. 3200 has higher contrast, but what doesn't at 3200? The 1600 is a candidate for regular use. I started a thread on this at APUG, and there has been discussion about the longevity of these negatives and whether a dip in C-41 stabiliser after fixing would be better than straight PhotoFlo. It's the old thing about there being little or no silver in the film, and silver inhibits fungi, so the stabiliser contains one of the imidazole anti-fungal drugs that one uses for yeast infections (I think I read it's miconazole - Monistat in a drugstore). I've got XP2 negatives developed this way three years ago that were treated with PhotoFlo alone and there's no sign of mould.
Today I'm trying to finish a roll of 35mm XP2 at 3200 just to see what that looks like. Unfortunately we have a blizzard, so it will probably be all the usual suspects as subjects.
C.