I caught site of an old copy of Amateur Photographer earlier, it was the 6 August 2005 issue, so a little over 18 months old now. The cover promised a review of the Nikon D2Hs, and referred to it’s "almost limitless burst depth". This burst depth was actually 50 4.1M JPEG images, taken at 8fps.
Now some 18 months later Canon are releasing the 1DMkIII which has a burst depth of 110 10.1M JPEG images, taken at 10fps. That Nikon now appears somewhat sedentary in comparison.
Time to go and ride I bike I think. I just have to decide between the Unit and the 456.