The big pic has me scratching my head a bit -- the MG the soldier is carrying looks like a SAW, but the rounds in the feed belt appear to be .308. Are M240s being issued with SAW-type forends?
7.62 would make more sense in another way: The belt-chute for that caliber could readily be scavenged from minigun systems; I don't know of any such assembly for the smaller .5.56 round.
Not so far as I know, though Barrett has been product-improving both the M240 and the M249, and they may have come up with something along those lines. But what you're really looking for is the Navy Mark 48.
7.62 would make more sense in another way: The belt-chute for that caliber could readily be scavenged from minigun systems; I don't know of any such assembly for the smaller .5.56 round.
You must not be familiar with the XM124 *six-pack.*