Building a bin cage attachment. Advice?

[Mousenibbles]

Right now CB is in a large bin cage that's working quite well, but as always I know I could do better for her- I bought another smaller container to make an attachment, thinking I could just stack it on top like other people do.

What I failed to remember was that I made a top opening cage! The lid is how I get her and her stuff in and out, so if I stacked another container on top of that, it'll be a pain and a half getting it open... D'oh.

What I'm thinking (It'll be complicated....) is of stacking the smaller container on one half of the top, and connecting it by tube- then altering the other half of the top to have hinges and swing up and out.

Does anyone have complicated cage bin building experience? Any advice, thoughts?