Any offerings in the works for a CVN77 or 78

Bush is Nimitz class CVN. It shouldn't be too hard to modify an earlier one to meet her specs. Ford is still being built, I can see her when I cross over the James River Bridge at Newport News. As a new class, there isn't really anyway of telling what the final product will look like for certain.

I you want to make a Bush, just build a Reagan with "77' instead of "76."  Check a few photos online of the Bush for any detail differences and give it a shot.

The Ford is a different beast.  Only 3 flight deck elevators, island is set more aft than Nimitz-class ships.  There are design renderings and photo conceptions online, but it would be a major scratch build attempt over a Nimitz-class kit.