Build a building at user-defined point??

This is a crazy question, but I know it has an answer somewhere, whether in the vaults of Blizzard HQ, or in somebodys mind here. When you are playing a normal map and you go to build something, you click build on your peon, and then select the building you want to build. Then you go to place the building on the map. When you click it then issues the build order to the peon to build it at the user-defined point. Now, is there any way to skip the whole clicking on buttons part? How would it be possible to just suddenly ask the player to build a building somewhere, and then an invisible units is issued the build order? I know it is possible, or else we wouldn't be able to tell our peons where we wanted our buildings placed, but how would you make it so that it would prompt a player to place a building?

You could make an ability based on the 'mini<building>' item ability, give it a hotkey, make a unit with no model have that ability, make a unit of that type for the player, force them to select it, force the UI key of the hotkey, and then the building will go where they click.