However, there's one thing you need to test first: can you QI
IDirect3DRMDevice3 from IDirect3DRMDevice(1)? Or do D3DRM Devices have
the same kind of restriction (down-QI'ing only) as IM devices?
I've written device QI tests (quick look: http://pastebin.com/5bpRizmr need to remove the last boolean flag column as it's unnecessary now) and you can query up-down across all versions.
Now that I know that thunks are preferred, I'll do just that and reply with the changes here as soon as I can.