Using Ripple for assets accounting, loans, deposits, stock exchange, etc If Ripple can handle money as exchanger, is it possible to use it for other financial operations like assets accounting, loans, deposits, stock exchange etc.?
Ripple has a contract system under development. This will allow people to bind Ripple assets or accounts to a set of rules. This should be usable for most of the things mentioned in your question.

Loans, ideally, would be done just as negative balances on a pathway.