This whole thread is very interesting and I have learned a lot from it.

When is comes to "low cost" (cheap?), I am El Cheapo Numero Uno. I haunt Goodwill and have been able to pick up several PC power supplies and convert them to controller/LED power supplies. Yes, they are bigger, but usually I end up putting them in a plastic case from Walmart and making them look like Christmas presents scattered about the yard or around/in Santas sleigh, etc. I use one of the supplies to power 3 PX1 controllers and a total of 200 or so LEDs.

There are quite a few DIY entries on converting the PC power supplies. Just do a search for "converting PC power supplies". It is quite simple and they provide lots of power for little money.

BTW: The suggestion about using Cat5 cable for supply is good. I sometimes twist the pairs together: One pair for ground and one pair for positive. While this is probably not the best solution, it is OK for short runs.

If there is a short run for the data, I use one pair, one wire for the data and connect the other to the twisted pair I am using for ground. I also have used the flat Cat5 cable, which slips under a window.

Just a few thoughts for you to consider.