Kwik Fit (UK) offered a 'tyre hotel' last year, where they would store your summer/all-season tyres over the winter. I got the impression the marketing guys dreamt this up without speaking to the garage managers, judging by their reaction to having to store endless sets of tyres!
Anyway, I am going to switch to winter rubber in Oct / Nov and will store the tyres in my cellar.
There is something to be said for getting a set of winter tyres AND wheels though.
Firstly, tyres should ideally be left on the wheel once fitted, it doesn't serve them well to be taken off/on/off etc.
Secondly, you can invest in a thinner and smaller rims (and cheaper if you don't like exposing expensive rims to winter weather). Thinner rims are meant to be better in snow, and overall, thinner/smaller rims will make for cheaper tyres - 255/35 profile winter tyres are rather expensive!
Either way, winter tyres are a thoroughly worthwhile investment.