I was lucky enough to find a 50# bag of leca at a local hydroponics store. Unfortunately, it may become very hard to find soon. Apparently the clay is gathered through a process similar to strip mining and many people are refusing to buy or use it (understandably).

The gentleman working at the store had a recycled glass alternative, but he wasn't sure if it would be animal safe. I may have to go back in and ask if he's asked the manufacturer about that yet.