no control [...] over the amount of Bitcoin in circulation
Well, actually, there is a mechanism, albeit not one you can fiddle with quickly or in both directions. That mechanism is the difficulty level associated with "mining" a bitcoin. The system (IIRC) works to a schedule to make it gradually more difficult, but if there was some sort of central bank equivalent charged with manning the levers, there's no reason why it couldn't push out the schedule for increasing the difficulty. The net result would be equivalent to quantative easing, except that of course it would be be miners printing the "extra" money currency rather than a central bank.
I don't think that Bitcoin could work if the difficulty level was allowed to be reduced since that would be a fast track to devaluing it asymptotically to zero. Still, I wouldn't put it past the ability of some clever designers to come up with a new "alt" currency that does allow a kind of central bank role that could effectively control the rate at which new currency could be created---say by making it index-linked, perhaps?
Biting the hand that feeds IT
