I made up a foamboard model of some of the design changes I've made for my chassis, in this thread:
And I drew up a layout in eMachineshop:
The lower part is the bottom of the box.
The center part is the tray that sits inside the box, and holds the 2.5" hard drive, and has a hole for the heatsink to pass through.
The top part is the rear backplate.
The part on the right is the cover, and has brackets for the slim CD/DVD, and a hole for the heatsink and fan.
My aluminum should arrive by Friday, and I hope to start bending up this box soon.