I have a Dual 450 Gigabit Powermac that freezes during OS boot.

This machine will not boot into 10.2 at all. The boot will start, but after 30 seconds or so everything freezes.

None of the HD's are SCSI.

I am using a known good 30gb Maxtor HD with 10.2.8 that was pulled from a B&W.

This machine will occasionally boot into 9.2. It will invariably freeze after a few seconds. Usually, the machine will freeze at some point during the boot process (usualy within the last steps).
I am using a known good 6gb Apple (Maxtor) HD with 9.2 that was pulled from a B&W.

I have also tried to install 10.3 onto a known good 40gb Seagate (no OS installed, but "initialized" by 10.2.8) and the install process will freeze at the screen where you are asked to select the drive to be installed on.

I have run the Version 1 Apple Hardware Test CD multiple times and everything passed.

I have switched out the stock DVD-ROM drive for a known good DVD-RAM drive with no change in behavior. I have also switched out the HD ribbon with no change in behavior.

I have verified that each HD is set to master.

The machine is stock with the exception of 1 256mb Cruical RAM stick that is a pull from a B&W (and was also tested in a quicksilver). Graphics is a stock ATI AGP card. No Airport, 3rd party PCI cards or SCSI drives/cards.
BTW: I have rotated 3 different (tested) sticks of RAM.

I am using the smurf keyboard and mouse from a B&W.

Ethernet cable is attached. No other usb or firewire devices are attached.

Monitor is VGA.

I have gone into open firmware and done the following:

Any ideas on what my next steps should be in figuring out whats wrong with this PowerMac?