Just as good gun engravers make their own engraving tools, good gunstock checkerers also noodle up their own cradles - although there are "kits" out there, with clamps that go on a 2x4 that gets vised during the checkering ops.
Study up on the photos and make your own. Vastly cheaper and every stinking bit as good as say brownells 2x4 cradle, LOL. A pipe makes a slick one so you can really rotate it out to all the angles you really need.
I bought mine from Brownells, money wasted. It's a fine cradle, but easily could be made. I thought maybe a set of deep throated pipe clamps might make a good starting point. Haber freight sells some of those on the cheap.