You've only got four or five drive bays? in a server case? Harddrives can be placed in any bay, you know . . .

I have a Chieftec dragon series case with six 3.5" spots and four 5.25". Of course, the four larger bays either require a 5.25" drive or brackets, but brackets are nothing. While such a layout would pre-empt an internal dvd-rom drive, external models do exist. Since the main focus of the unit would be serving video streams from hard disk, a "permanent," internal drive would be unnecessary -- and the detatched nature of the drive would even allow for adequate hiding of the computer if also used in a home theater.