Following on from the, as pointed out, flawed idea for an r/c sub, how about a scale model on a non-operational one, but either with removeable sections to see the internal detail, a bit like the tiger tank (hachette), or even a half-sub, again showing the insteranls but literally being either 2 halves of a sub, or just 1 half, with a lot of intracite(sp?) detail