The tub is a large concrete mixing tub from Home Depot. Lowe's had some too, but they weren't as well made, and they cost slightly more. I got the wire from a local independent feed store. The springs came from a bolt shop. (I know... bolt shop??? Bakersfield is a big oil town, and they are all over the place. I bet Jack sees them too.)
Bass sells the 2 hole carrier with plastic tray for $28.10, my total cost is $42.00 for 4 holes. I'm saving $14 plus shipping, and my trays are deeper and more durable. The plastic they use is already becoming brittle.
They are time consuming to make, but it would go a lot faster if I weren't so picky- every cut wire is being bent over, with the exception of the door edges that meet in the middle of the cage lid. All bent wire is on the outside of the cages so if anyone gets cut it will be me and not a bunny.