I got myself from eBay the MB-D10 almost immediately once I received my D700. The MB-D10 comes with the MS-D10 AA battery tray as well as MS-D10EN for the whatever battery, OK, EN-EL3e which lasts for at some 1000 frames I think, or more. I haven't really measured it. I don't gain on the frame per second department on this grip as I don't have that special military grade battery. With the motor drive I can always carry an extra EN-EL3e and some AA batteries. So running out of battery shouldn't be happening. I like the grip but I think I even like it better if it's integrated with the camera. Just like the F5 pictured above on the right. The F5 is smaller and cleaner when compared next to the D700 with the grip attached.
I can't believe that the D4s was just introduced in 2014. With the introduction of D810 and D750 and a myriad of other Nikon products, the D4s just seems old, though the price certainly doesn't reflect that as it's still in production. Unlike the D700, which is really a 2008 camera and out of production.
I think the D3s actually makes sense plus if what I read is correct, there is some improvement in the high ISO area making it like 1.5 stop better than the D700 or the D3 which could be significant. The D3s with the integrated grip may actually be smaller than my D700 and grip combo.
A D3s makes sense to me.