This is a place I order all my foam from. I use a lot of it in my business, and they have great prices. You can get any size you need.

Here is a link that might be useful: Foam

I haven't had to use foam wider than the 24" JoAnn Fabrics carries yet. But these are a couple of the places I have looked at online in prep for the ottoman top I am going to need in a couple of weeks.

http://www.foamforyou.com/Open_Cell_Foam.htm
http://www.foamcenter.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=BEST_FOAM

HTH

I used this place awhile back, and they were great.

Here is a link that might be useful: The Foam Store