Velodyne does make some pretty spectacular subs. That's really great that you and your wife are both into sound & music - I wish my wife could appreciate sound more.
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However, I must respectfully disagree with your statement that (you fear) you'll lose your soundstage by moving your speakers any further away from the wall. Moving your speakers out away from the front wall will in fact greatly increase the depth of your soundstage and increase overall clarity & imaging at the cost of a bit of midbass reinforcement - though I'm pretty sure your impedance coupled transmission line Ospreys are "free-field" types that were voiced to stand away from room boundaries.
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In fact, your soundstage would be noticeably deeper were you just to remove the piano from between your speakers. Vocals would probably sound about twice as far away as they do now - especially with some absorption. Before you do anything with your speakers get some masking tape and mark where your speakers currently stand so you can put them back exactly as they were as well as using some longer inexpensive heavy gauge speaker cables to aid in experimentation if your current speaker cables are maxxed out. By all means try moving your speakers 3', 4', 5' even 6' away from the front wall - just be sure that you don't create a speaker/listener triangle where the distance between the speakers is greater than the distance from the speakers to your ears or you'll lose the soundstage perspective that your used to. Additionally, you might even try George Cardas' setup formula...
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http://www.cardas.com/content.php?area=insights&content_id=26&pagestring=Room+Setup
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Cheers!
