I checked around in five or six different TPSes, and didn't see "green off off red" or "g off off r" in any of them.
Specifically, the S5000PSL TPS (which applies to any of the S5000 server boards) jumps from 'g off r off' (0x28h) to 'off r off r' (0x50h), entirely skipping 'g off off r' (0x42h, if I am reading the decoder correctly).
For general memory/pci bus troubleshooting, I might try only one DIMM, and remove all possible PCI devices, and see if you can either get a beep code or display that way.
It appears that the motherboard was defective. I've gotten it RMA'ed now.
Funny how no information on that specific error code exists.