Honestly, I say let's just skip ships. The GM and most of us aren't going to use them. You guys would have them and they'd remain unused for the majority, if not the entirety of the RP. This is a very land based game, and the GM is against it. Nuff said. 

I would also say it's not equivalent to no ships in 40k. We can easily travel to each other's nations on foot in this RP. Space ships are a must in 40k.