Hey hamburgerhelper - you might find this
http://invictus-innovations.com/i-dac interesting. The guys at Invictus will be the first to admit they are computer scientists, not artists, so the site is not super slick -- but their future plans are nothing but exciting!
I've got some Protoshares myself. I'm anticipating big things to come out of Invictus.
I'm pretty sure exchanges will be made possible as a DAC using their technologies. Mastercoin
http://www.mastercoin.org/#features will also enable trading as a layer on top of the Bitcoin network. Unfortunately both solutions are pretty far from release.
I think it's worth mentioning both as possibilities for trading a year from now but something else will probably need to be done in the interim.