This is a post that I have been looking forward to writing ever since I came across this thread on M4C. Battle Arms Development is working on bringing their own forged AR-15 Lower Receivers to market and I have no doubt that they will be excellent. These lowers will be compatible with the truly excellent short throw selectors. They may even be available as 80% receivers at some point. There have also been hints of a billet receiver popping up some time in the future.
Check out Battle Arms Development!