Interesting ideas, James.
I made two more last night. It takes about 15 minutes once you have a template for the holes. You can get these containers with lids really cheap from the dollar store. I like cheap.
Depending on how large you make the holes, you can have the cups sitting at the bottom of the container (and water from the bottom) or have the cups suspended in the container to avoid over saturating the roots(watering from the top).
Really, the biggest advantage to this contraption is in keeping the cups from falling over.
Frank