Thanks Galadriel and Juliet. Although I am sure it would work, the bottle-solution probably would be frowned upon by the HOA - too cluttered looking. I already am pushing it with the containers as it is since they weren't supposed to be between the buildings (which they are) so they might not like the appearance, but it is worth trying on a small scale and seeing what they say. And Juliet, the design you were talking about is somewhat of a take-off of the desert refrigerator/swamp cooler which might not only have the watering effect but a cooling effect in the middle of the summer. Interesting! And after posting my question, I was thinking about painting one side (only) white or with the RV reflective paint and facing the black side towards the sun during the early and late season, and then turning the white towards the sun during the mid-summer. The pots are situated against the condo wall and side by side, so it's not like the different colors would be blatantly obvious, if you know what I mean.
Thanks again for the ideas!