bigjohn - thanks! We can reach into the corners fairly easily, but I like your idea of a sloped bottom. I thought about it briefly, but it was all starting to get more complicated than I'd first intended, and I hadn't built anything in a very long time. Let me know how it goes! We've talked about possibly adding more cages in the future (separate from this one), but I'm a beginner, and I only got jumbo browns since they're easy to sex!
Baachus - I was considering building my own trays out of wood and linoleum, but it looks like I'm going with plastic bin lids instead, from IKEA. The plastic is light, and will be easy to clean. I'm putting shelf lining down on the wood slats below the cages so the poop trays won't blow away (very windy where we live)
We're going to drill holes in the bottom of the leftover bins and use them for planters.
sporttees - It's approximately 2 feet deep, 5 1/2 feet tall at the back, a little over 6 feet in the front, and 6 feet across. I'll be posting diagrams and some basic instructions to my blog hopefully in the next month or so.