Oh, so that's what the backpack is good for? Doh! 
Cloud saving should be a totally different issue. 
All this has been hashed out here:
That adds JSON to the list, which was discussed as a reason better than CSV for N-dimensional data, and makes it easier to export in a Snap! native XML.
I'm normally not the guy to suggest rolling our own, but cloud variables definitely seem like the solution we'd want. Plus, a very very basic version isn't technically very hard -- conceptually a backpack function is just a variation on storing a project, but the amount of data storage as well as the ramifications of just storing more raw data like sounds and images mean that we'd need to proceed somewhat carefully.