When I searched for groundpod I only got the Skimmer available on the market, and it looked not stable enough for my use. (I have never tried it, so I assumed...!) Some other danish photographers had made their own design and here is my homemade copy of that design. It is made by stainless steel and easy to push through sand, seaweed and small stones, when I crawl on the beach, trying to get closer to waders...!
Some friends have mounted a camou-shelter to hide behind when crawling.
For your inspirations...!