lo-fi (chris),
orange county speakers can hook you up with a great butyl rubber surround that will last a long time and that is nearly indestructible. i had some vintage sonab hi-fi speakers that originally had foam surrounds that had disintegrated due to age. they replaced them with the butyl surrounds and it didn't seem to change the sound of the speakers but they'll last a lifetime now.
best regards, tube (richard)