This is step 1 in an enclosure system I'm working on for my D300VS, but even if you don't plan to enclose your printer, they add a nice aesthetic finish to the bottom. Print 2 of the "y-z" plates, and one of the 'x' plates, which has an opening for the wiring mast in the X corner.
There's about a 1cm air gap between the plate and the bottom of the bed.
The plates are held in place via tight friction fit on the motor mounts.
Fusion360 file is attached if anyone wants to improve... Please share if you do!
UPDATE: Check out the remix by santier74 at https://www.thingiverse.com/thing:3280341 if you're looking for a version with the whip opening on the other side.