Do you mean to have the minimap show the entire map, like in this screenshot from StarCraft 2 (I think):
You will be able to make a minimap with a static view point. In the video you see this at 0:40. Although in the video it is a large map, you can render that to a minimap as well. Is there any specific reason why you want to render it to a trapezoid? Thanks for the feedback!