Word for a small space/dwelling that is much larger on the inside than it appears from the exterior

Now accepted into the lexicon, and deriving from the Doctor Who example (I saw the first episode in 1963):

Tardis noun

...

2A building or container that is larger inside than it appears to be from outside.

Example sentences:

‘It's a bit of a Tardis – two townhouses knocked together, with a long gallery at the back where the garden used to be.’

‘Stretching away at the back of the house – like the rural equivalent of a Tardis – are 17 acres of land.’

‘Though the building looks very spacious from the outside, the staff have dubbed it the Tardis in reverse, as the interior is more compact than you would imagine.’

‘The experimental house has been compared to a Tardis.’

‘The mind is like a Tardis, far bigger on the inside that it appears on the outside.’

{ODO}

I love tardis, first episode about 1977. Was 1963 the second doctor? If it's reached the lexicon, I think it should be "tardis" like "laser." In Doctor Who lingo: Time And Relative Dimensions In Space

I think you're stuck using an adverb unless you like tardis as a noun, such as:

"This apartment is surprisingly spacious."

The other option I like, as long as were talking architecture/real estate is maximizes, but this doesn't generalize.

This yard maximizes it's space.

Because of extensive shelving, the walk-in closet maximizes its potential.

As an aside, esoteric words are rarely a good idea for marketing.