I use a "temporary" spare from a Grand Cherokee (mid '90's?). The tire size is a T155/90D16. I picked it up at the salvage yard for $15.
Diameter is pretty close to my rears (295/45-17 drag radials) and bolt pattern is 5 on 4.5".
It stows easily in the trunk with factory mount. I got a scissor jack at the junkyard too (can't use the bumper jack with 'glass' bumpers smile