Yep--and just to reassure you, it's more than an idea on my end... I designed and maintained a critical system a few years ago on a large K/V store that used th

Yep--and just to reassure you, it's more than an idea on my end... I designed and maintained a critical system a few years ago on a large K/V store that used this method, and it worked without a hitch. We never even needed to think about the fact that the documents within the store were comprised of various schemas from several generation of the application (except when we wrote and tested the next incremental link the upgrade chain).