Take a look at the Magpul ACS stock. Very similar to the LMT stock except the lower battery compartment. KAC is using it on their M110C offering to USASOC (no KAC comments please
).
Both the ACS and the LMT have about the same cheek weld, the ACS seems a little heavier, but the ACS works better in the prone and it's far easier to access the batteries in the tubes.
It's available for $100 at several places.