Now this is a little more than a regular TARDIS suggestion, so I would like to know what you think about it:
First of, it is the tent that appears throughout the series of Harry Potter movies and books and it's bigger on the inside, so why not?
Also, I would like to suggest that this tardis won't make the usual sound and effects, and instead it would disappear immediately (similar to appearation).
Furthermore, I suggest two more models for this:
The marauder's map for a monitor, and a desk lamp for a de/remat lever (I didn't have any better idea for it)
I would love your opinion on this suggestion!