Thanks for the response.
I had about two hours free to do a little more research, so I called Canon about the camera you mentioned. First, Canon told me that if I want true night vision (IR) that I have to go to their professional line. The least expensive IR camera they have right now is the XF100, which retails at $2,999, or $2,499 on Amazon (as of 9/20/13), and it's a fairly large camera - about as long as my forearm. If I was still attempting to film documentaries I'd spend the money and be done with it. But that's way out of my price range and wouldn't fit in my fanny pack when I'm taking the kids to the zoo.
Canon suggested that I could get excellent low light recording with a consumer model. They also recommended the HF-M52/M50 but added in the HF-R40/R42. I took a look at some YouTube videos and I must say it's impressive what you can see using the R40 in low light, but it's not in the same class as a camera with true IR. When recording outside with no more light than what is provided by a full moon, the Canon's will allow you to see the outline of the trees you're standing in front of, which is not bad. But a camera with IR will reveal the leaves on those trees.
It looks as though the only company currently making consumer priced cameras with IR is BenQ (Bell and Howell). They are selling on Amazon between roughly $200 and $230. The newer model is the Bell and Howell DNV16HDZ, and the older model is the Bell & Howell DV900HD. While these cameras do a good job with the night vision they are pretty weak in all other categories. Instead of being grey scale, they cast a purple hue when in night mode. To make matters worse they don't power off the night vision sensor when you switch to regular mode, so some images come back with crazy coloring.
I'm pretty surprised that there are so few options available. When I purchased my Sony, it seemed like one out of three consumer cameras had the night vision feature. Today, if I want true night vision, the only options I see are to either wait for a used Sony HDR-PJ790V to come down into my price range, or to buy the Bell and Howell DV900. The PJ790V is smaller than my existing camcorder, but it's still bulky. The Bell and Howell would do a great job with night shooting, and is small enough to make me happy, but I'm sure I'd soon be out looking for a second camera to use for filming everything else I like to do (it's not even stereo).
Any other suggestions folks?