Digital Cash....

Has anyone looked at basing digi-cash on the processing power required to handle it? In other words, instead of basing it on real cash directly or simply setting up a 'flat' standard (is there an accepted technical term for this?) base it on the MIPS that are required to process it in a given time (say 1mS)? Seems to me that this would provide a standard that was universal and verifiable by any organization that chose to spend the effort to do it. It would also add another layer of isolation (since the only person (sic) involved w/ real cash is going to the be processing sight paying their electric bill).