Try Litko's BaseMaker™ tool. Choose to have your base made from any of 20 different materials. You can even get special features like rounded corners on your bases.
Long story short, these are great bases. I get the 0.8 mm plywood and put a flexsteel under that. The flexsteel is self-adhesive, its easy and it works great. I use the heavy duty magsheet in cigar boxes (free from local smoke shop!) and that's how I store it all.