There was, way back when, talk that Dave-B's not operating off a carrier would have their lift fans removed and replaced with an additional fuel tank to substantially improve the range when in a conventional mode. There has been no mention as far as I'm aware recently so I expect the plan was dropped. Supposedly utilising the lift fan slot and the driveshaft as a power source the B could carry a very high power energy weapon.
I wouldn't expect to see it for another 20 years though!