Wow! Both of those are really cool. We're looking at the PVC pipe options right now, because they seem the easiest...
I really want to find an autowaterer because we have pretty hot summers. I'm worried that if they dirty their bowl, spill it or something, and I'm not there to clean it up... Ugh. Scary.
I'm sure I'll find something though. If not, it's time to be inventive!