RIA/Armscor have said they will be introducing one, but not when and I am tired of waiting.
I have a CNC mill so am considering making my own version available for sale.
Should I make a dozen or a hundred?
Expect a price of about $75.00 shipped, hard anodized aluminum.
Yes you will need to drill and tap the top of the action.
A no D&T version may be possible but I doubt many folk would want to pay the high price.