This is the state of affairs. If all your data is client-side(i.e. no item/money exchange between players), I have something ready to test, and least for mission persistent data(i.e.as long as server does not crash and mission is not restarted). It extremely light weight, without any error handling. Your problem will be integrating it with SPON_Money, but that is no biggy. PM me an email address and I'll send you what I have, with a few notes on usage and poking it into SPON_Money.
For true client data sharing(i.e. full item/money exchange between players) the issue is more complicated, as you would really like to store all data on the server and verify each transfer. It gets a bit messy for my ability.