This is what i use to carry my calls ( shows, hunting, flea markets, ect ) and keep them from being damaged. it will hold pots, scratch boxs, tubes, strikers and this low cut model will hold a box call just pack some soft foam on top. they are a dime a dozen on ebay
http://www.ebay.com/itm/Vintage-12-Tapes-Brown-Faux-Leather-8-TRACK-Storage-Case-/161203491278?pt=LH_DefaultDomain_0&hash=item25887a11ce
Gary