no HD wont sell that carpet.. discount has rolls of grey carpet or balck but its not that nice

gulf fabrics i belive has what you want or www.selectproducts.com

now non hardening caulk to mount the subs? dont use any liquid to mount the subs, that will just be a mess. if you need some sort of sealant, use weather stripping. call some audio shops, most of the time they have some of the gasketing that is left over from other subs.

imho ive never needed any gasketing for my stuff