First of all most of those 'big box' stores have white fire cable now. then it's painted. It's not a violation to paint it per 72. The indentification is still under the paint, dry fall paint just flakes off, some don't, but it's still there. With few AHJ local amendments and gadfly's considerations for the paint to damage the jacket, you are being paranoid about painting it. I appreciate your passion for code compliance, I don't feel this passes the straight face test.
Why are you intentionally over spending your customers money by only using plenum? You are really ripping yourself off. If there is no need/requirement for plenum , keep the cost difference for your self!!!!
Speaking of Plenum!! I had yet another contractor tell me that an open ceiling required Plenum because, the air circulating in that space eventually makes it back into the return air duct work. He tried to hang me with the GC and a building inspector. The inspector delayed the final inspection a day let me 'fix' 10000'+ of various cables. After politely requesting a code reference, (ummmm well, ummm), we allot on the same page. Turns out the other guy thinks the last job specs he had were code mimimum, he felt enlightened and tried to share.