Yeah, the cans are a pain and lots of work. However, they are free. Being a incredibly cheap design its hard to beat free.
Also, most guys glue all the cans together. I don't see that as necessary. They also force the air to go directly through the cans vs just anywhere in the panel. I also see this as unnecessary. I think if you put the cans in the collector in an organized manner, pinch them at the top and bottom with a 2x2 or something, and you should have a good enough collector.
You could definitely cheapen up the design if you had a wall that you could work with. Unfortunately, I do not. So, this is what I came up with.