Safety Harbor Firearms is working on a new version of its Kompact Entry Stock (KES) that will work with AR-10/7.62×51 platform rifles. The following videos show a rifle with the prototype KES and associated buffer, carrier and spring being test fired.
There are a variety of these kinds of compact stocks on the market for the AR-15 platform. A number of them require the use of a special bolt carrier group and buffer. The KES is one of those.
Although information on the AR-10 version of the KES is relatively limited and certainly not finalized, the existing KES can suggest where the company may be taking the new model. Existing KES models can be had with two position (open/closed) or four position adjustments.
The existing kits ship with a stock assembly, buffer, buffer spring and bolt carrier. These allow the rifle to function correctly with the reduced buffer tube length. Kompact Entry Stock pricing for the AR-15 is $350. I would expect the new .308 version to be in the same neighborhood.
For those not familiar with Safety Harbor Firearms, the company is based in the Tampa Bay area. They manufacture a number of different gun products including .50 BMG conversions for the AR-15 and short barreled shotguns like this Kompact Entry Gun (KEG).