In that case you may want to take a look at a Dahon in your LBS - see it up and folded, same with the Montague. See what they're like to carry and how much space they'll take up in your place.

I don't fold my Dahon right the way down as I'd need to darry it downstairs in a case if I did - then carry the case upstairs, then go downstairs.....

The Montague looks a little smaller when fully folded but a similar fold is possible with the Dahon and they do sell some carry cases to fit.