I found this great 5.25 inch storage bay/junk drawer for a tower over at Engadget. Not the most visually appealing thing in the world, but quite useful. Could be easily modded with a custom front. Would be a great addition to any old or new machine.

MacBook 2GHz Intel Core 2 Duo w/ 2GB DDR2 RAM & 120GB SATA 5400RPM HDD
Canon Rebel XTI
Google Cr-48 Beta Laptop