I switched from Campy (8) to Marchisio when 28tooth cogs became hsrd to find. An added advantage is that I can replace the cogs individually, since the big ones seem to wear more with me.
With Marchisio, you can change the spacers to get the cogs to work with any indexing system, eg Shimano mech and changers with a Campy hub. This is not so crazy, if you want a really long rear mech and maybe bar-end shifters.
Torelli.com has more info