Finally an update :) It's not so much as I've been procrastinating a little because my other project is underway (the Aluminum Foundry) and I'm hoping some of my first parts will be for this machine HERE (probably re-do the Y Axis Rails as they flex just a little) - after you're done checking this update out - check out that project :)
Here are the linear rails and trucks I won off eBay - these are very nice and should be perfect for the Z Axis - I need to make a linear stage for the router to be mounted to next!