Interesting on the 777, as unless they find a way to really up the ZFW (at the expense of fuel) or push the MTOGW up, the 777 would be limited to about 50,000 pounds less payload than the MD-11. Possibly more. One nice thing about MD is that they all were built with a cargo-capable floor, so pulling out the seats, etc, actually makes the BOW less for the freighter. The 777 would need a new floor structure which would wash out any advantage not having the weight of seats gained, so the BOW listed on the Boeing web site would not go down -- could possibly go up.
Be interesting to see how they work around these issues.