What's even a wilder stab is someone having one and knowing what it is. I have hundreds of them but don't know what board they go with unless they are physically with the board and most aren't. Good luck.
I'll dig through my collection and see if I have one.
On a related note, I recently bought a SC846 storage case and a SM X8DT6-F motherboard without the shield. As luck would have it, the case came with the correct shield already in place. They came from 2 different sellers so it was pure luck.
No, sorry. That appears to be rare config. I've checked ebay a couple of times and found nothing that's even close enough to mode without looking ghetto. Have you tried contacting Tyan? That's a long shot too but and email is cheap.
Or you could just run without one. It doesn't serve any purpose other than looks and maybe airflow control to an engineer. I have one system that's been running for years without one because I couldn't find it when i was putting it together. Found it after the MB was already in the case but didn't feel like going thru the trouble of removing it again. Never missed it. But if it's for somebody else, that's a different story. Good luck.