Hi Mike. Thanks for the message. A friend and I just made one for my bike a couple of years ago. We took a standard front plate. cut it short and used a wooden former to shape the roll over. Then welded and ground the curve smooth.
The grill was also a standard part but cut short, carefully bent to shape and spot welded.
The filter was a standard one cut and reglued.
We only made one but hopefully you can find someone local who can fabricate one. It's pretty simple.