I woke up with an idea but its just in thought stage.
Your idea is basically for a bank. I'm not sure of the practical workings for that, if only for the fact that if I know the DVC pool is a perpetual buyer at price X, what happens when I'm happy to sell at X-1 (i.e. the pool would need potentially unlimited funds).
Im not sure its a bank, since its not offering to hold funds for anyone (apart from investors) It would be closer to a money exchange if there is a FIAT equivalent but your comment made me think..it has co-operative elements as well.
Its boggling my brain a bit so I'm off to have a little think and try to get this down on paper. Sorry I dont have a clearer view yet but in my head first thing this morning it all just worked.. if I could just find that "Eureka" again Id be right lol