Campy's square taper design works just fine and that's why I'd assume they never went to a splined BB. FSA does however make an ISIS Splined Campy Compatible Carbon crankset. Plenty stiff and very light if you really don't want a tapered design.

Shimano 9 speed splined cranks will also work fine with Campy 10 from what I've seen people running so I wouldn't think of it as a drawback.

I have 7500 miles on a Chorus BB and Campy Crankset without so much as a squeak FWIW...