This sounds like a great idea, and very resourceful. My only concern as you go forward is the moisture control and heat - common bin concerns. With such a small bin, it could either dry out or get overwhelmed by moisture very quickly. Also, a little heat can affect the whole bin. Since you have kept worm bins before, I would use your experience to eyeball the mixture regularly, and really monitor the moisture levels. I would also feed only in certain sections of the bin so that the worms always have someplace to go to escape in case something decomposing begins heating up.

I would keep both a spray-bottle and plenty of extra bedding available and ready to go in case a quick moisture adjustment is needed.

Do post pictures, and let us know how it goes!

It is hard to tell what plastic containers you are talking about. At target.com maybe do a search to find a picture of the two tiered boxes and past a link to them. Seeing as how the Wriggly Wranch worked so well for you maybe just get another one. I am thinking of moisture build up of the cabinet area under the sink as opposed to the airy garage. It is fun to see peoples worm farm designs. Structural strength is a key idea.