I finished this little rebel Gretchin from Fox Box! He's one of a handful of free miscasts I picked up at ExiliCon in 2015, and the casting is a little rough -- but this I attribute to it being a miscast. He was missing the weapon or pack meant to be slung on his back, so I replaced it with an old metal Ork bolter. He's the guy standing on the thing, with the previously painted ones hanging around in the background.
These photos aren't great (and my paint jobs are a bit shaky), but hopefully you can get the impression.
Here is a size comparison showing these models with other generations of Gretchin:
Left to right, these are Fox Box, RT metal, 2nd ed. plastic, RT metal. I don't really own any more modern grot models.