15" Plus stands?
I would suggest Ohm Microwalsh Talls. I'm a Vandersteen fan, and I'm really glad they didn't fit into my space, otherwise I would have never tried the Ohms! Ohms were not my first choice, but they were worth a try due to space limitations. They are fantastic speakers, and are similar in sound in many ways to the Vandys, BUT with a huge sweet spot, and easy to place - I now prefer the Ohms.
I have also tried countless brands of speakers - countless (every NYC store, hi-fi shows, recording studios...), and the Ohms being a home demo went unnoticed. I read a 6moons.com review, talked to the reviewer and decided to try - nothing to lose (4 month return policy) since I didn't want to settle with anything else that I'd heard.
The Talls are 36" tall/6" square, and the Short version is 23". I've heard the Shorts - don't let their size fool you, they can take on any monitor or floorstander in (and above) their price range - but I recommend the Talls.
It is a home demo, so let me know if you have any questions.