In reply to Ninian:
the new Mantas are definitely narrow, but I never tried the old ones, so I can't compare. There's definitely a huge width variation in the different Scarpa products.
Last year's Snow&Rock catalogue usefully noted the breadth, heel width and volume of each boot they sell on a NMW scale. It seemed quite accurate. I haven't seen this year's catalogue yet, but it might be worth checking.