Well I had tried previously to use my Raspberry Pi to run my Mendelmax through Pronterface. It worked ok until I tried to print something, then the visualization totally killed the Pi and the prints would be impressionistic blobs :)
I saw an article recently about how to setup a Raspberry Pi to run a RepRap style printer, and it basically combined a bunch of different installation steps into one guide. There were a few hiccups with the steps but I was able to figure it out, the most important part was how to disable the visualization in Pronterface! Basically you just search through the pronterface.py file and remark out any line with gviz in it.
I've been printing since this morning and it's been running great. Another nice thing is that the latest version of the Pi image includes a WiFi configurator, and the ability to overclock the pi, along with some major speed improvements.
Before even opening up a browser would almost kill the Pi, now it's zippy and even in the middle of printing it usually hovers around 25-30% cpu usage, so I'm very happy with the results. I've got a WiFi adapter on order which should be here tomorrow, and then I should be able to make my RepRap totally stand alone!