Unlike the A-6 there is no need to build a dedicated KA-5 because the bomb bay provides room for the drogue/hose unit. KA-6s had to remove their DIANE avionics complex to carry a drogue/hose making them unusable as a strike aircraft. Apart from the easily removable unit in the bomb bay the only other thing a tanking A-5 needs is the buddy tanker control panel which space for was designed in from the start.
It’s one of the advantages of the linear bomb bay that you can just roll in a train of fuel cans with the drogue unit at the end and presto a tanker. My thinking was to use this to make a modular fleet of strike aircraft. After the late 70s rebuild the RAAF Vigilante force is a mix of strike (two wings of 48 aircraft each) and recce aircraft (reinforced squadron of 24), which have different navigator cockpits adn the direct view sight on the recce version (plus of course the ventral canoe). The strike aircraft use the bomb bay to be configurable as:
# conventional strike: three fuel cans in the bay and bombs, napalm, rockets, etc on the wing pylons (3,600 gallons internal fuel).
# submunition strike: full length dispenser in the bay for either anti personnel, anti tank or anti runway loads (2,715 gallons internal fuel).
# PAVE TACK strike: vertical packaged AVQ-26 PAVE TACK laser designator in the forward end of the bay and three fuel cans. Up to four PAVEWAY III laser guided bombs under the wings (3,600 gallons internal fuel)
# WILD WEASEL strike: APR-35 radar homing and warning receiver in forward end of bay with anetennas in short ventral canoe (also plugging into other RWR antennas on the aircraft) and three fuel cans. Up to four AGM-78 Standard ARM under the wings (3,600 gallons internal fuel).
# stand off strike: Project Long Arm TV guided glide bomb with auxiliary fuel in bay (3,520 gallons internal fuel).
# nuclear strike: nuclear weapon with two cans and fin assembly in the bay (3,305 gallons internal fuel).
# refuelling tanker: two cans, buddy can and 78 feet hose reel unit. (3,595 gallons internal fuel)
Like the RA-5C the recce aircraft is configurable between imagining recce and electronic recce and has 3,600 gallons of internal fuel. Plus I’m thinking they have to put a few Vigis (6-8) aside during the rebuild project for conversion to NR-349 standard in long range optical photography and signals intelligence.