Well, I don't know if the Crucial RAM I ordered would have worked or not, but I believe it would have even more now since the RAM in my controller was Micron (which is Crucial)...
The controller I ordered from eBay showed up with not only a RAID controller, two HDD, dual power supplies, and dual T1/E1 module, but it also had a DSP-II module and the expansion E2T card, so I needed two 1GB memory modules not just one... And I didn't want to wait until next week.
Which led us to scavenge into the graveyard pile and found an old Dell laptop with 2GB of RAM... two random (although matching) 1GB DDR-667 memory modules by Hynix... Threw them in and it booted and passed all memory checks and showed 1024MB of RAM in the bootloader. I am currently installing 8.1 software and will move my working database from the old MXe to the new MXe III later today or tomorrow.
Looks like Mitel is really hitting us up for the name on this one...
EDIT: Software loaded, SysID chip moved, and database restored... Took me a while to remember how to change the E2T IP Address, even though I am one of the authors of the tutorial here on how to do it, but it's all up and working now. But it is now 5pm, so it's time for a beer or three and next week we go through the migration to 9.0!
Moral: You don't HAVE to buy the RAM upgrade from Mitel, any industry standard 1GB DDR2-667 (PC2-5300) unbuffered, non-ECC SODIMM module will work. They are under $20 on Amazon, Newegg or MicroCenter... Although I don't know how it might effect warranty, support, or maintenance contracts.
Now, would I do this for an actual customer or do I tell them they must buy a $300 stick of RAM that is approved by Mitel? Guess I will leave that to people above me to make that decision.