Is there an indestructible dog toy?

Trying to find the indestructible dog toy that's interesting is, well, very difficult.

Exhibit A: The items/toys that Lucy chewed through in one morning at my office:

It's a struggle keeping an Austrailian Shepherd/Jack Russell Terrier Mix occupied and interested in a toy;really it is. The Kong, at first, was brillant. I'd stuff it with treats and at first it took her a good 10 or 15 minutes to figure it out. That lasted about 2 weeks. Now she can wriggle those treats out of it in like 2 minutes flat...or less. Perhaps I need to find some softer treats and use more peanut butter to make it more difficult.

Then there are the stuffed toys that squeak. She *loves* those but destroys them in minutes of aggressive chewing and playing. Today at lunch I bought her a little soft stuffed toy for dogs. She went crazy for it. I could even leave my office door open and nothing could take her attention away. But then I heard a ripping sound. It lasted a good 5 minutes, more than most, but then I had to take it away from her. She was upset. I tried to distract her with this new "indestructible" chew toy - Hard Core Fire Hose. It's a red stick with a squeaky interior. She liked it for a minute or two but got bored. She wanted me to play fetch with her, which I can't do while at work, at least not well and it's distracting.