I did try to mount the Truvativ cranks on my Koxx Red Devil just to see if they would fit. The Truvativ cranks fit but they would not tighten up against the spacer. There was a 1/4" gap between the spacer and the crank (there is no gap when I mount the Truvativ cranks on my muni). So it looks like the hub on my Red Devil is a little bit bigger than the one on my muni.
I think it was one of Roland’s post on the German forum that talked about the variances in the Koxx hub.