Some time ago, I wrote about the U.S.S. Enigma, a Constitution-class variant capable of cloaking, a tool of the nefarious Section 31. Originally, I had envisioned the black ship you see at right as the ship's standard look; when it cloaked, I was going to swap the black ship for a non-painted, translucent model. This was Steve's suggestion, and while I love it (and could in fact still do it), I really wanted a version of the ship that could masquerade as a legitimate Federation vessel. So here's the U.S.S. Enigma in standard Starfleet livery. I now imagine the black ship as the cloaked version, but since it's not truly invisible (as the translucent model would have implied), maybe this, in-universe, could represent a more or less powerful cloaking device than the standard Romulan model.
More importantly, I'm getting better at applying these finicky little decals.