Can you have a huge 3D soundstage in a small room?

I have similar dimensions, but have the speakers situated on the 13 foot wall. The imaging is often outside of the speaker, given the material, of course, and the depth of soundstage is very good. I attempted placement similar to yours, but found much restriction in all areas that you are trying to improve on. Plus I was seated so close to the speakers.

The distance I now have is 3-4' from sidewalls, 8-9' from front, and nearly 20' from rear wall. The ceiling is a mere 7', which is the largest drawback. Yet, I am still obtaining a very musical presentation.

I have no experience with Vandi's, but I have heard complimentary discussion regarding imaging and disappearing.

The only way to get close to what you want is to put the speakers on the short wall, 7-8 feet apart. Then pull the speakers well out from the wall, 5 feet or more, and treat the first reflection points on the side walls with absorptive material. I don't think you wanted to hear this, but it's the only way to achieve what you're looking for. Long wall placement in a narrow room will never create a deep soundstage.

I agree your speakers need to be on the short wall. I rarely audition a system that has a better soundstage than mine and my room is 14x15 so I think it is definately possible for you to get a terrific soundstage. It takes A LOT of experimenting though! It doesn't just fall out of the sky - unless you are way luckier than me! Arthur

Ok, a little harsh sounding, and maybe a little critical to boot, but most of above is pure hoggy-washy...
The last statements refering to using the "short wall" setup for getting a huge soundstage are not fact, in and of themselves. Infact, as an acoustical engineer, I'll tell you that the front wall reflections have much much less detrimental affect than the boundaries between you and your speakers!(sides,ceiling,etc). Usually, a minimal diffuse/absorb solution up front will deal with any problems there.
Without any applied acoustical treatments in small rooms, it's usually easier to get a better soundstage and imaging using the "longwall" setup...all things considering. If the rooms are too narrow however, there's other challenges in bass modes and proximity to the front speakers that are considered however. If you do do a short wall setup, you'll either need to have the speakers "in a bit" from the sides, and be sitting closer in approximation to the speakers for a good soundstage and imaging. Otherwise, you must deal with reflections, preferably more diffusion in small rooms, going to more absorbtion in larger rooms, as is most often the case.
Of course, it's all a balancing act with acoustics. But you can get a massive sounding accoustic, with severe acoustical modifications and applicaitons. Mainly, you need to absorb all the excess bass in small rooms, which often aint happenin'! Therefore, there's too much bass overhang and reverb. Then, mate that with the case that most people aren't getting anywhere near flat response in small rooms from their seating possitions, don't/can't properly adress "Q" in the room, nor deal with reflections and balancing diffusion/absorbtion/etc right, and have a seroiusly challenged setup all around, and it becomes a near impossiblity in most cases to get a world class sound!
Oh well...you can always higher an acoustical expert.......
In short

Thanks to everyone for the input. I will try the speakers on the short wall. It doesnt really work ergonomically but if it will sound great I am willing to give it a try. I think I have tried just about everything for the long wall placement. So what works well for wall treatments? My dealer likes the RPG wall panels for absorbtion and diffusion. Any thoughts?

Thanks again