Virtualization

[TrabacchinLuigi]

I was looking into virtualizing lists and i surely did check if mvvm toolkit was providing a solution to that, unfortunately there isn't or i'm incapable of finding that out.
But i did find some proposals here an issue with all of them (unfortunately some of those websites need to be accessed via wayback machine or some other internet history or cache service)
before this wisdom is lost and need to be re-implemented again i think it's a good idea to include it here, maybe the same, maybe reimplemented, but i feel this is the right place for it