Not in EaW. Only in FoC and only if you play as empire and only if you're still using the crappy old way of making maps by placing units directly. use multiplayerstructremarkers! If you mod in a marker that's for an ISD, MonCal, and an Aggressor, then, whatever faction you select, you'll get one of the ship for your faction to start (but requires minimalist coding) XD. So yea, its much better than just placing the unit.