Pelican 1055cc case (modified)
I ordered this case
without trying it out. The dimensions said that the G-Pad will fit with 1mm to spare on top and bottom. When I got it, the tablet did not fit quite as well as I expected - I could stuff it in there against the foam liner and close the case, but it required some effort and did not feel like the seal would work well.
I decided to modify the case with a Dremel.
You can see the results in the photos below - it doesn't look pretty, but it fits the tablet very well. There is a relatively thin amount of padding on the top and bottom, but it is still decent, and the tablet should not sustain any damage if it falls, in my opinion. There is still some space on the left/right, so it moves a bit, but there is a good amount of padding so I'm not too worried about it.
Overall, if you're looking for a tough/waterproof case, this is a great option if you don't mind 5 minutes of work to make it fit. This mod can also be done with a box cutter if you don't have a Dremel.