In my experience there is only moderate correlation between speaker or driver size and the size of the soundstage the speaker throws. There are small bookshelf speakers with two drivers that when placed on stands and positioned properly produce a huge soundstage.
However, I must admit that the largest soundstages I have heard are from giant speakers with multiple drivers. Von Schweikert Ultra 11's, big Wilsons, and a couple other huge speakers. Another speaker that generates a huge soundstage is the MBL 101 E.
I'm running Thiel CS6 speakers and they throw a respectably large soundstage with a small number of drivers.