Attached are photos of a dust boot I fabbed the other day when my original finally bit the dust (sorry).
I also attached the cutting file and more pics (due to pic limit) on the next thread entry below for those that want to modify and improve on this. It presently fits a Milwaukee router.
My constraint was to keep the dust hose to the rear of the gantry. It seems there are several aftermarket and DIY dust feet that exhaust to the front but I didn't want that.
While it is not transparent being all plywood it has not been a problem for me so far.
Note that the original "dust foot elevator assembly" has been reused and "floats" inside its own pocket for easier fit-up and strength (no weak fastener points).
The bottom 3 layers I simply glued together and then screwed the top two on. I used a piece of HVAC duct flange for the connection to the 4 inch exhaust hose.