Hi Rik,
No, there is so little in it, I found on a few occasions accounts of using a 10 spd sram cassette with 10 spd campag group. I bought the cassette & compared it to my mates 10 spd campag & the difference is pretty much non existent.
I have used this set up now for a year on my cross bike & is perfectly fine.
You can however get hold of campag spaced cassettes to fit shimano freehub – american classic being one.
cheers