Slick!
Seconding mixedgas's "more outputs" suggestion. You've got tons of spare GPIOs on that micro; just route all of them to pin headers. (Bummer that the LPC1343 only has one UART...)
The first DIY DAC that I built had some very basic onboard constant-current drivers built in, which was super handy for reducing overall number of parts in the projector. A dumb low-side CCS doesn't take much in the way of parts - just a BJT, opamp, and some resistors. Flexmods are nicer, but something homebrew will get the job done in a pinch.
edit: also, making the UART header pinout-compatible with these things
https://www.sparkfun.com/products/9718 makes software debug super easy.