Golden the Ship Was- Oh! Oh! Oh!
It doesn't have to work, only has to barely fly. It is deterrence that is needed.
After all, how many have actually seen with a mark 1 eyeball an actual nuclear explosion? Sure, lots of videos and pictures, but those can be faked. The current bombs, even if the old ones actually were field tested and worked, are only simulated. But everyone believes they do work, which is currently sufficient.
So for this 'bomber', take a Globemaster, wrap some weird shapes around it, put in some way to eject munitions so people think it is capable of carrying conventional weapons, and put the savings into the black budget space based unmanned weapon deployment system called "Skynet", er... "Voyage to Mars" or some such.