If you try to compare the features offered by Blender Cycles with older and more mature render engines like LuxRender, you will notice that Cycles is in fact a very young render engine, and still has a lot of development ahead. But, with some creativity we can work around some of those missing features to render really impressive images for architecture. For instance, just take a look on the image below posted by marcoG_ita at the Blenderartists user forums. He is using a clever technique posted at the forums to fake IES lights in Cycles.
I strongly recommend you to check out the tutorial about fake IES lights on Cycles, which will be useful to render rooms and interior scopes.
More views at the forum post.
