The way I understand it, miners add transactions to the blockchain in exchange for a fee and for newly minted coins.  The rate of newly minted coins was determined by the early adopters of bitcoin and cannot be changed unless 51% of the miners decide to fork the blockchain.

If this is correct, then in theory, a cryptocurrency can be made with the inflation rate determined by the number of transactions included in a new block.  If many people adopted this currency, it would achieve transaction speeds far greater than any other cryptocurrency.

I believe that such a currency, made for fast trading rather than holding value, could be a good complement to Bitcoin.  It isn't feasible to buy a cup of coffee with bitcoin and wait see to confirmations of the transaction before you drink the coffee -- however, this would be entirely possible with Fastcoin.