Two companies have recently entered commerical production of ABS panels and I thought I would mention them here:
www.realgesso.com
www.higden.net (contact doug higden for information via the email on his website)
I haven't tried either of these panels though I have samples them in my studio. They are certainly superior to anything I personally can make myself. If you are unsure as to what ABS is, there is a lot of discussion of this substance on this Forum if you enter a search of the term "ABS".