McN,
You always have to sell a system, not wiring! I will never wire a person's house unless I cover both wiring costs and at least 15% of the equipment up front. I got screwed over and over again with clients trying to be smart and bid every aspect of the job even after you made a deal!. If a client awards me with the job I get it to the end, no such thing as universal wiring and I use coded labels ( when I can!)There will always be a smart guy out there . Protect your lively-hood! Let the Best buy customers do the Best buy thing and good luck!