Not that I am aware. Ocassionaly I have some but not right now. I use www.foamsbymail.com. Nice selection of foams and easy to deal with. They are in MI.
I pick mine up or get the minimum for free shipping so I am not sure about their shipping charges.
One thing I thought I would mention since I have used both the cubes and the regular foam. I use cross-linked high density polyethelene. Easy to cut and you can get a near perfect fit plus it does not absorb moisture.
Mark I'm not sure of any sponsers but you can Google "pick-n-pluck foam" or pluck foam and get many hits on foam sources. If you can match up a size thats close I know Pelican has polyurethane open cell foam and polyethyene closed cell foam replacement sets and sheets for their cases. Hope this helps Buck