what kills soundstage depth?

Speaker placement. Without question.

Away from the back wall and side walls. Try them closer than you have them presently. Experiment with toe-in.

There are many resources for suggestions. Google "speaker placement guide" and you will get a list of links to useful alternatives.

Sorry for any confusion caused, but I accidentially posted supplemental comments on your system thread with the photos.

add tube? tube is known to improve soundstage depth

Hi, nice setup, and yes you should have depth "if" it's on the recording. What kind of music are you listening to?

One more thing I'd try is a big quilt over the TV to see if it's contributing or not. (in addition to all your other good comments above) Speaker placement first though.

Cardas has a nice guide posted, might be useful: http://www.cardas.com/content.php?area=insights&content_id=26&pagestring=Room+Setup

Final though, is everything new? might need some breakin time...

When your speaker is close to the wall behind it, the depth perception is minimized. Pull any speaker (and I mean ANY) forward and you'll hear (see) more depth. Personally, I could not give a rat's ass about soundstage. I NEVER think about that when I'm at a live show-why should I care with my hifi?