I haven't heard of the glue thing... that might be a myth.
I do find it surprising that people on a bulldog message board talk about tennis balls and take pics of their dogs with tennis balls. My dog isn't even a year old, but I'd estimate that I'd be a couple hundred dollars richer if a tennis ball would last even 10 minutes with my mutt. Dog toys are way too expensive, and way too weak (in general).
I did discover a great ball resource for serious chewers. One of the parks that I take my dog to every day has an outdoor ice rink (that's canada for you, eh?) that doubles as a lacross court in the summer. Those heavy rubber balls they use are always being launched into the park and lost.... then found by my mutt!