Hot-rodders would refer to this as a "sleeper." I think it is a sound idea.

You could take sandpaper to your derailleurs and cranks to grind out the name of high-end components. Without a sticker proclaiming "XTR" or "Ultegra", most people (including me) couldn't spot the difference between the good stuff and the cheap stuff. Anything highly polished, though, just tends to draw more attention. Good wheels are hard to disguise, but you can pull labels off and maybe do a hippy paint job.

The three things that I think will be most difficult to disguise properly: the saddle, the pedals, and the grips. The best way to hide the saddle might be to just wrap it in a grocery bag. I see that often enough on rainy days that it wouldn't stand out as anything strange. If you use platform pedals, you could have the nicest Campy equipment available and thieves probably still won't mess with them. But clipless pedals look like good targets and they are easy to steal. And I'm really not sure how you could wrap your bars in a way that is ugly enough to deter a thief, and yet still comfortable and functional. Perhaps some really tacky purple grip tape?