I only used the grey 8 x 12 baseplate in my CAD drawings. In reality, that piece is only available in green, but you could also use standard plates (rather than baseplates), and use anything as long as it covers the same area. eg. 2x(6x24), or 4x(6x12). When I put them into my Ikea display case, I didn't actually use a baseplate at all. The front edge is a little bit flimsy, but can be reinforced with some 1x10 plates underneath the front.
Unfortunately the price and availability of pieces fluctuates, but it was a reasonably cheap display stand when I made it a year and a half ago. Take my design as a starting point, see what pieces are cheap and easy to come by now, and just adapt it to suit your needs. Once you have a stand that you are happy with, please post a photo so that we can see what you came up with. Good luck
Edited by Splat, 11 November 2012 - 12:52 AM.