Almost all rear hubs are available with a SRAM/shimaNO or Campy freehub body/carriers. Most manufacturers offer brand specific freehub bodies/carriers separately. Then, there is the aftermarket parts for older/discontinued hub models.
Finding the separate bodies 'may' be a bit of a challenge without resorting to mail/internet ordering.
http://www.modernbike.com/itemgroup.asp?igpk=2126202982&TID=367&gclid=CODk3N2k67gCFapAMgodO2sA9g
Campy-to-shimaNO freehub body show and nomenclature here in Campy tech catalog specifications.
http://www.campagnolo.com/repository/documenti/en/SPARES2013-PART_C-06-06-13.pdf
Oshner should be able to supply you the correct cassette body if you furnish them with the model/approx. year of your hubs.