I have spent some time as of late researching foam matting and considering making my own mat. I have not seen much discussion on the web on how to accomplish this. One of the key materials you need to make your own mat if vynil. I am not in a position to buy the vynil yet, but I ran across a great deal on vynil and wanted to share this just in case someone else is in the same position I am and is looking for vynil.
GovDeals.com: Gym Floor Covering
There is enough vynil to cover a gym floor. I am sure it is enough for anybody looking to cover grappling mats. Hope this is useful to someone.