A 12 Pack of Beer.
Canadian Origin - Specifically the Toronto borough of Scarborough.
1970's and 1980's bottled beer came in 12 packs with cardboard handles that stuck out the top - making the package look a lot like a suitcase or toolbox.
Similar phrases - Souix Suitcase - Hammer Suitcase - Big Nickle Suitcase etc.
A term mainly used by hosers.
Lets hit the beer store and pick up a Scarborough Suitcase.
That hoser is on his way to the Bush Party and he's got himself his Scarborough Suitcase.