UPDATE:
So I had the chance over these past few days to demo the following systems, Solid Drive and Onsia. I demo'd them at friends/colleagues houses - and of course told them how amazing their speakers were (you never insult another mans audio to his face). I won't mention too much about the set-up, as to protect the privacy of my friends.
Here are my humble reviews.
Solid Drive
First Impression: 6.5/10 very cool technology and immediate "wow" factor. The Solid Drive sound transducer can be attached to almost any solid material and create sound. Apparently it is a combination of some highly sophisticated sonar tech and very powerful neodymium magnets.
Sound: 4/10 I know there is going to be a sacrifice in sound, but, even for background music, these speakers were not convincing. The passive equalizer module did not seem to improve the sound, and the sound-field was fairly narrow, with an obvious drop in clarity from only several feet away. Overall, felt a bit weak.
Installation: 6/10 the installation for all invisible speakers is going to require some handy-work, Solid Drive not excluded.
Price: 4/10 i would gladly pay 3x the price for a speaker that sounded 3x as good.
Overall 5.5/10 although Solid Drive can be attached to almost any solid surface and make sound, the sound quality is closer to generic computer speakers or everyday ipod docks than audiophile sound found in traditional home theater. For the price, the "wow" factor does not outweigh the "sigh" factor.
Omsia
First Impression: In-walls. The specs were decent (you can check them out on their website), the set-up was nice-er. Very spacious house with a large open floor plan. I immediately realized I could not tell where the sound was coming from, which was good. However, it did not exactly fill the room with sound either.
Sound: 5/10 much louder than Solid Drive, with a definite increase in bass response and an impressive sound-field. My friend had me guess where the speakers were hidden in his walls, and I only managed to locate 3/8 from his living room. Unfortunately, the sound itself was only a bit better than Solid Drive. Whether a fault of the house (which had high ceilings and lots of open space) or the speakers, I could not fully tell, but the music felt dull to me...and cheap.
Installation: 6/10 My friend said it was easy. I'll take his word for it.
Price: 8/10 CHEAP. A 5 pack of in-walls for 240$?!
Overall: 6.5/10 Very inexpensive speakers for immersing sound, but cheap immersing sound. I'd would say it is comparable to your run of the mill bose system.
This is where I am at so far. I guess my only question is: if you have heard these speakers, do you agree or disagree?