Rather than continue to struggle with the lousy low-light performance of the RasPi camera, I bought a purpose-built security camera, the D-Link DCS-942L (also sold as the "Cloud Camera 1200").
This camera is an Ethernet/WiFi device; although I found its WiFi reception so lousy I had to cable it to hardwired Ethernet. It gracefully supports both. This Camera has a smart web server running on it. Among other functions, it can FTP clips and stills to another computer when it detects motion in a pre-selected area of view. So I use this feature to upload captured motion clips to a PyBall, and use the PyBall as a web server to conveniently display what it's seen. The home page displays a live video feed, and the Events page displays a thumbnail collection of all of the motion-detection clips it's captured.
I have a sub-repo posted on Github with the components for this web server. It's very basic and clunky right now, but if you're proficient with Linux you should be able to get it to work.