As a fan of minecraft I have already discovered a very good builder, using blocks to build submarines, with some functionality, Gran Bazar from BF3 at scale and some other interesting stuff that could be loved here or there. If you wanna try them, they are mainly for online using, but i think you can easy use them in a singleplayer map.
Planetminecraft.com
PD: If you see the ast 2 images, they are refereed to a funtional space ship, as seen in StarCraft, but it needs some tricky tutorial to get the missiles working etc... I know how to do them working but it´s a little bit tricky.
