I have contemplated this myself, and will offer an unsolicited (albeit friendly) critique of your design.....
The current design has two sharp edges (points, really) where the corners of the hole grab the pipe.
This will surely introduce tiny crescent dings all along the shank of all of your pipes. Either ease the edge or introduce a 1/8" chamfer? I personally think the best way to store a pipe is down, and upside down, so the draft hole drains (away from your bite) and the dottle coats the bowl.