I never thought that it was possible to make a TARDIS dress that is actually bigger on the inside, but just like science, the internet eventually makes all things possible.
[Insert joke about entering the TARDIS and fiddling around with her circuitry here.]
The cosplayer you see wearing this awesome TARDIS dress is Sasha Trabane. It was painted by Andy Coyle for the recent Arisia science fiction convention in Boston, MA. Needless to say, it won two prizes at the event.
I think it is safe to say that this dress can not be outdone. But of course, the internet will surely find a way. And when it does, we will share it with you.