It's quite likely someone else has already suggested this, just seems like an easy way to build multiple buildings with one click would be - Click and hold (like you already do) to rotate the building on the spot Dragging the mouse away from the initial point to plot out a queued grid of buildings of that type, at the orientation you rotated the initial building to. Terrain collisions/impassables are removed from the grid without blocking the overall plot.
Seconding this. I believe SupCom had this feature and I loved it. Great for making nice orderly patches of energy planets or small rows of factories.
As I was picturing it I realised you would actually need to lock rotation before dragging the box, if you're still able to modify rotation as you drag out you'd essentially be stuck in one dimension, one row of buildings, set by distance from initial point. You'd need to add shift once you're happy with rotation to start the drag, but this fits in with the existing UI concept of using shift for queuing so it probably wouldn't be too awkward.
