I am. Well, sort of. I only use Campag ergos as that’s the campag bit that I actually specifically want – the rest (eg mechs, cassettes, hubs etc) I don’t really care whether they’re Shimano, SRAM or Campag.
As such, I’ve done both Shimergo (10 speed Campag shifters w/ 9 speed Shimano mechs/cassette/chain) and now a mix of 10s Campag shifters and 10s SRAM mechs, cassette, etc which works spot on. It also allows me to fit a clutch mech which is great for when it’s used as a CX bike.
Both of these get around the wheel problem by allowing the use of Shimano/SRAM type cassette fittings.
IME you won’t really find campag disc hubs or at least not easily, other than the Hope ones you’ve mentioned which any Hope dealer will be able to order in for you.
EPS will obviously limit the options further (and from what I’ve heard, I’d wait for the next version as it still seems a little, er… quirky 😉 )