It is purely hypothetical, nobody has yet started work. For that matter, no one has yet done any new 3d object for SH4....
The mod forum is more technical. If someone started serious work on brit subs, mod forum would be the place.
But for Brit subs, we would need:
- Exterior models for subs
- interior models of control room and conning tower. Some british subs (U-Class) did not have a seperate conning tower and were entirely conned from the control room, but I suppose the larger ones had one.
- British sailors with beards and proper uniforms. Or we could take just the ugliest SH4 guys and pass them off as brits :rotfl

ducks and runs away) but they would still need new uniforms.#
- A brand new voice pack with both southern fairies and northern bastids. And some scotts and whatever other strange people populate that island.
- I wonder wether SH4 actually would support the addition of a new playable nation with new awards, ranks, bases etc or wether one would have to replace the Americans with the British.