So its been well documented the compatibility of 11 speed system cassettes:

(http://velonews.competitor.com/2013/09/bikes-and-tech/drivetrain-compatibility-hidden-in-plain-sight_303199

There is also quite a lot on the so called Shimergo system, using 10 speed campagnolo levers with 8 speed shimano gear. I have used this setup and was pleased with the shifting and the small cost.

Looking at the charts showing cable pull Shimano 11 speed and Campagnolo 11 speed are very close. Has anyone tried running either 11 speed shimano shifters with campagnolo derailleurs of visa versa?

No. But herself uses 11 speed shimano cassettes with Chorus EPS with no problems.

Yeah 11 speed 105 cassette with chorus, campag cassettes overpriced and limit your wheels a bit.

Yeah I understand the compatibility with cassettes, but I’m wondering about mixing shifters and rear derailleurs.

Cable pull is 2.6 with Campag shifters and 2.7 with Shimano shifters. Pretty close, close enough in theory to work but I was hoping someone has tried it!

It’ll work at one end of the cassette or the other, or in the middle. But not across the whole cassette. You’ll get 3 or 4 acceptable gears, then the rest will get progressively worse. It’ll be “better” with a shimano mech, thanks to the floating top jockey, but you’ll run out of range on that fairly quickly.
You might get an improvement by spacing the mech cable clamp, but you’d have to play with that yourself.

Not sure if the out of position would be enough to quite skip gears, but it’ll rattle and clatter like a f**ker.