Leapers makes one for like $60 through optics planet
Personally, I find bringing a pack and resting the rifle on top of it works far better in the field than a bipod. Along with a tripod when you need to get above natural ground obstructions is where I think it's at... not that you asked for opinions... To the actual question at hand for a panning bipod the Atlas V8 @ $220 isn't terribly expensive?