Disclaimer This is for my models and is not tested with other models.

I made this to fit both of my current uploaded models as well as the upcoming raspberry pi pipboy. It uses TPU for the feet but you could use other plastic if you don't want them to be soft. 
 

Non-Printed Parts

M3x5 Screws - QTY 12

7mm Washers - QTY 8

1mm Craft Foam

Mine has a fair amount of post process done to it. Here are the steps:

Dry sand 200 grit

Dry sand 400 grit

Wet sand 400 grit

Black uv resin coat. (Foam brush black uv resin from resin printers. Lightly layer and cure until happy with build up)

Wet sand 1000 grit

1 coat clear matte finish.