Im thinking carbon magazine tube, composite fore end and buttstock. Im sure components in the receiver can be aluminum instead of steel. Who will be bold enough to make this niche gun?
Then that leaves one small problem; someone to develop and promote a 6mm level cartridge based on the 308 marlin express. Or wildcat it, except brass doesn't exist.
Somehow do that around 6lbs rifle weight and top it with a 1-8 NX8.