Mmmmn Miche actually do a full range for Shimano and Campag, as well as their own:
Shimano 7-8 & 9sp
Campag 8,9,10sp
Miche 8 & 9
Sure you can interchange the spacers but then you have to make sure the width of these are the right thickness as there is a variation between the cassette sprockets them selves as well as 'ramping', you would have to experiment.
There also is another Italian maker really nice stuff called Tiso who do 8-9 speed in both Shimano & Campag
Miche cassettes are invarably cheaper than the genuine brands and good quality