Bilt-Hamber in Essex do a three products, intended for the car industry but they work a treat on bikes too; their Dynax S50 product would be ideal for inside frames, and the can comes with a 600mm flexible injection lance that sprays in four directions tangential to the hose, so you get *all* of the inside of the tube.
It's intended for internal cavities that don't get exposed to UV. Essentially, anticorrosive wax that might see any light has to have UV stabilisers put in, but that limits how much other goodies you can then put in the wax. This hasn't got any so it has more anticorrosive additives instead.
Go have a look at their website. This is my first post so I can't link