Ive seen a recent mod,
gear_hud ,that does the gears of war hud system with the icon in the middle, but it doesn't do blood splatters. What we really need is a mod that we can configure to show blood when we crit or when we are crit. and I do beleive this would be a very popular add-on.
Optional features could be show blood when your hp falls below a certain point, and for death knights, show blood when you corpse explode.