I think I mentioned in the last post that I'm building off of the JGRO CNC design. For my initial try, I'm replacing the alignment blocks with aluminum. I'm also looking at potentially replacing the lead screws, but that will likely wait until I've assembled things and tinkered with the design a bit more.
The biggest changes are related to the electronics and software. I just got a Tiny G and I'm waiting on some NEMA 23 motors from http://buildyourcnc.com/. I'm planning to drive these from an old PC power supply I've got - I may need to get a second one depending on the overall power requirements. Right now I'm looking at different CAM and CAD systems that will work well with GRBL.