Mark,
I do not think that you can power up the BL3s without first powering up the BV8, but I am not an expert.
Yes, I have "woven" some of the larger pieces into primary residences; specifically, a recent system consists of BV7 (w/BL7-4), BL9s (front), BL3s (rear), and a BC2 in a 22' X 20' X 12' h room (library/media room) with exposed structural ponderosa pine "vigas" and a "beehive" fireplace. The system is in an historic 350 year old adobe structure where I was not allowed to alter the walls for wiring. Initially we were going to use the B&O wireless solution but we figured something else out that the historic commission agreed with that allowed for direct use of the B&O cables. The BL9s are a good choice based on the size and outstanding performance. The BC2 is well suited to blending in with a more traditional setting but still making a statement at the same time. Once again, the BV7 video panel and the BL7-4 are integrated into enclosures (in this case existing "nichos" with doors one above the other) to take this dominant element out of the environment for audio-only situations. I see this as key, particularly for a traditional setting. In this case the doors for the panel and the center speaker are motorized and connected to the Lutron lighting and shade control. Hiting the "light" button will dim the lights, draw the shades, and open the doors to the panel and the 7-4. It is a very nice set-up and can be overidden at the Lutron control panel for any combination of lighting, shade position, and door position. This residence has BL5s in the livingroom as this is an audio-only room. Given the "in your face" presence of the BL5s, I have found that it is difficult to integrate the BL5s in a subtle way unless the room is large and that these are the only audio/visual pieces in that room. No pics to offer as I recently sold this project and do not have permission from the new owners. My advice, for what little it is worth, is that the audio-video system should not be the only ultra modern part of the design as it will stand out too much. An ultra modern thread in the functional elements can be continued throughout the residence using the existing traditional elements as a continuous backdrop. This will give a visually and philosophically harmonious design experience. For instance very simplistic stainless steel fixtures (think Dornbract, KWC, etc.) and appliances (think Gaggenau, Miele, etc.) in a kitchen combined with traditional cabinetry (using simple stainless steel hardware) will reiterate the underlying "moderness" of the design approach without being unifromly "modern" and allow for sightlines to systems such as a BC2 to appear "normal" or "expected" and not "Wow look at that modern piece over there!". This is what I have found in my experience. I also try to include some works of abstract art to bring the composition together.
I like the contrast of functional, ultra-modern against an old (or traditional) structural fabric. The "functional" parts being the kitchen, bathrooms, audio visual systems, lighting and window coverings, each representing state-of the-art technology in an otherwise old structure, preferably with some "patina" such as rustic original flooring or elaborate moldings with lots of paint obscuring the detail. B&O used to show such examples in their catalogs and I think they should do this again. I am currently looking for a new project and perhaps I will put up some photos as it progresses.
Seek simplicity and distrust it. Alfred North Whitehead