Ahh variable pricing… that has come up in several discussions, but my gut tells me that it is further away. The trickiness there is to provide a guarantee around price through the life cycle of a transaction. It is possible to shoe-horn something in, leveraging fixed pre-defined amounts; and then conditionally determining which to leverage based upon the environment concerns.
To answer the question about monetising streams, I am going to tag in @jchow, who should be able to give you a more authoritative answer than I can. 