The hard part is the reputation transfer (or voting, or embuing). If you have 30 A coins and B puts 10% "juice" in them, does this mean you can use them like 3 B coins? Or can you convert them somehow? What happens when C puts "juice" in B? Or A puts "juice" in C? The potentially recusive nature reminded me a lot of Pagerank, but basically you will end up with coins that are a mixture of different coins, and you have to find an algorithm that converges.
I also think the economics are going to be really funny because suddenly price does not depend just on supply and demand, but your coins are going to be better or worse for certain purposes depending on how the emitters vote. (They are basically giving out vouchers to a bit of their surplus depending on what you buy.)