hey - i ordered some grande caps from lava lite a few years ago by calling them. give them a call!
Great—I was just looking at their site but didn't see caps in the parts section— thanks so much for the tip, Brad. I'll call them first thing tomorrow!
I know this isn't much help, but a few years ago a remember there was a website that sold replacement caps.
Called Lava Lite and they are shipping me one — for free! Amazing customer service. thanks for the help, folks!