I used the software mfussi described in thing#15276 to get the elevation data from Google Earth, then I used a small VB program to flip the data over and scale the number of points down. I then imported the data as surface files into openscad. This image of texas is 87 tiles. I have higher resolution tiles that I will post soon that will make a 5'8 x 5' textured image of texas

Slice it as small as possible to get the detail. I have it scaled to fit the thingomatic.
The excess around the edges should be .4 mm thick and easily cut off. (side effect of using surface() in openscad to import the tiles)

The VB program I wrote to scale the elevation data also let me cut out the parts of the tiles that weren't part of Texas.. Ill post the executable and the source if anyone is interested.