A lot of things that were supposedly impossible were cleverly coded in. For instance, you could have a luminator simulate multiple light source blocks. I could think of a couple ways that could be done, although it would be awkward and stupid. Perhaps someone could think of an elegant solution.
EDIT: Pseudo-air was exactly what I was thinking of.
There are some things that cant be simple "cleverly coded in", sometimes it takes a overhaul of the whole fragging thing that its limiting the process. Besides if it would have been possible i bet there would already been something to simulate this effect, because trying to bring a 15level illumination to a whole room its something a lot of people would have messed with around.
Also "seudo air blocks" could cause some wonky behaviour when trying to put blocks in those spaces, even not allowing to put anything at all in there.