about the 3dmap i remember an old game using it, it was "epic".
there was just the top and bottom face of the cube, seen in long perspective, but the mess was to understand the z axis position (the relative high).
Personally i still prefer,maybe just beacuse i'm more used at it, the front/rear radar style, cause i find it more intuitive, but if we want a 3d solution this may work better: a circle seen in perspectiv (that represent x and y axis, like a map), a flshing central dot -our position- and the dots of the otherships around us with a line that connect the dots to the base of the radar, the circle i was talking about. The lines would probably help a lot to understand the z axis position, but the all stuff should be anyway enough big or it will become just a mess