A few years back InRange TV did a series called "What would Stoner do?" where they used updated parts to come up with the AR that Stoner would have designed in 2015 or thereabouts. The GWACS/Cav Arms polymer lower caught my attention but as luck would have it they were no longer being produced. Evidently I wasn't the only one interested because InRange got together with Brownells and KE Arms to produce an updated version. Looks like it will be released at SHOT Show 2020.
https://www.brownells.com/guntech/wwsd2020/detail.htm?lid=17958
https://www.brownells.com/guntech/wwsd2020/detail.htm?lid=17958