The storm that formed on Monday night had a pretty well defined MCV near Greensboro that lasted for about 2 hours, and maybe even longer (although it wasn't detectable by radar anymore). The animated GIF I took with GR Level 2 Analyst is a bit big, but a pretty cool animation. Click the image to enlarge it.
Update: Here's another MCV that formed in Oklahoma a few weeks back on April 30 2012. In this scenario, a strong supercell thunderstorm was embedded within a line of storms and was able to take on an incredible amount of rotation. As a result, the storm produced a strong tornado near Medford, OK that evening. This radar animation depicts wind velocities, which show wind moving towards and away from the radar. Green indicates wind moving towards the radar, and red indicates winds moving away from the radar. When you see intense green/red colors side-by-side like they are in the first few frames up near Medford, OK, that indicates strong rotation and a likely tornado. Notice that the rotation broadens as the animation advances, indicating that the rotation spreads out as an MCV over a wide area. Click to enlarge.