Troy industries actually makes one.
I'm thinking of developing a railed HG for the Sig series, the real question is how many can be sold?
What would you make them out of Sean?
I'd love a rail that you can mount a REAL bi-pod on ... unlike the piece of crap that is on a stock one ... just garbage!
There is a factory adjustable(?) one too that is different than the stock oem model that comes with the rifles - I saw TSE had one in stock about a week ago... I think $260ish....
Most likely the Versa-Pod.
No, it is an oem or other Swiss-made option. I've seen a few of the Swiss guys here run them on their Sigs.
I've not paid it much attention other than noting it is different (and looks significantly more substantial) than the oem stock one, because I never use mine (I've actually removed it from the handguard).