Also thinking of doing this as well. I can think of a few different options on how to mount it to the header without welding on tabs. I'll have a look later on since perhaps it can be mounted to the oil pan somewhere else.
The problem is... where to find heat insulating material like the oem heatshields. They are 2-ply. I think any regular sheet metal will heat soak.
This would be an easy product for a vendor to come up with.
I am thinking of using 2 of the oil pan bolts for mounting the plate. I also think I could use the header fiberglass wrap around the plate to stop heat soak. I need to find a suitable strength of sheet or expanded aluminum for the plate and then go from there. I'll post pics if/when I do this.