Betfair (sports bet exchange) can handle more transactions per second than the NYSE. They invented a technology called Flywheel which, apparently, allows them to do it with only 2 x $50,000 servers.
They wouldnt touch bitcoin with a bargepole, but if someone could hire their programmers, or license their technology things would be much improved.
http://www.hpts.ws/papers/2007/HPTS%20Workshop%20-%20Betfair%20-%20Flywheel.pdf50,000 transactions per second.