Campag 8-speed cassette spacing is 5mm, shimano is 4.8mm, over the 7 shifts that's 1.4mm error. If you set it up so that it's correct in the middle if the cassette it'll be out by 0.7mm at top and bottom. Small enough to not really matter. Shimano top jockey wheels are built with a fair bit of slack in them so if you use one in your campagnolo mech it'll help absorb the error. I've got a bike with this setup, works really well. 95 Veloce groupset with shimano r-500 wheels, shimano hg-50 8-speed cassette.
There are lots of inexpensive campag 8-speed wheelsets around as 8-speed campag hubs are incompatible with 9,10,11. The problem is finding 8-speed cassettes. Shimano still make 8-speed stuff.
Campag 8-speed cassette spacing is 5mm, shimano is 4.8mm, over the 7 shifts that's 1.4mm error. If you set it up so that it's correct in the middle if the cassette it'll be out by 0.7mm at top and bottom. Small enough to not really matter. Shimano top jockey wheels are built with a fair bit of slack in them so if you use one in your campagnolo mech it'll help absorb the error. I've got a bike with this setup, works really well. 95 Veloce groupset with shimano r-500 wheels, shimano hg-50 8-speed cassette.
There are lots of inexpensive campag 8-speed wheelsets around as 8-speed campag hubs are incompatible with 9,10,11. The problem is finding 8-speed cassettes. Shimano still make 8-speed stuff.
PS if you go 9-speed can I have your ergo levers?