It really is worth it to have one made for you. Here is a pic of the one hubby did for me; it took him just a couple of hours, and the most expensive part was the acrylic sheet for the insert he cut for me (around $30 IIRC.) I love it so much, I had him cut a second insert for my other piecing machine so I can swap them out. I now pair this table with its twin in my sewing room to give me lots of quilting space.
http://www.quiltingboard.com/t-17094-1.htm