UPDATED . . .
Not much of an update but I have been running things over in my mind trying to get a handle on how this is all going to go together. So I spent the last few days thinking about access, mobo placement and GPU placement. I decided a few days back to salvage the mobo tray and use that to mount the mobo. My biggest issue was fitting the GPU and back panel of the mobo. After some careful measuring and cutting, I have been able to fit a place for salvage from the original case. This will allow me to mount the GPU and access the mobo back panel.
Here are some initial pics. I will need to do some pop riveting to keep it in place. Until I get all pieces prepped, I will just be dry fitting.