The one in the photo is a custom milled Delrin pump from Chipley Custom Machine, he doesn't do PGP work anymore I believe.
Punisher could do one for you, as could any of the competent airsmiths that aren't swamped for work right now.
You COULD look at getting one of the older knurled metal pumps, or take a look at the Cooper-T "Nasty" pump. It's big and burly and I'd love to see ya break on of those. I believe it's Delrin and the one I tried was a perfect fit for my big goofy hands.