Paint will adversely affect the sound of your bass. I have a bass that had a thick "poly-goo" gloss finish on it- once removed and refinished properly it was like a new bass- a much better sounding bass that had more volume and character of tone. As you surmise, the more paint, the more dramatic the loss of tone and volume will probably be.
I'm not sure about the wrap- sounds like a neat idea, but I'm sure there would be some kind of loss of tone or sound depending on how thick the stuff is.
Big warning: Be sure to find out how that wrap would be applied- if it is shrink wrapped with heat it would be a really bad idea. Also, be very mindful of things like your soundpost- it most likely fall down in the process if/when you remove your strings.
Also, prepare yourself for the onslaught of slings and arrows from those who will condemn this idea as folly!