This is an older thread, I know, but I recently had to research this this issue, so I thought I'd comment.
I followed the Wendlands' lead and bought a Canary device and will use it in our Class B, with a few caveats. A number of Class B bloggers report using this device or a competing product such as the Piper NV, but they typically run it off their inverter, in conjunction with a cellular air card. For efficiency's sake, we will do the mod so that we can run off the 12 V system with an adapter. We will turn our attention to that after we get our lithium retrofit completed.
Meanwhile I've been testing the Canary in my office and it has worked well. The manufacturer seems to have improved the severe oversensitivity issue that reviewers of the first gen version complained about. I have not gotten any false alarms, but I do reliably get a text message every time I'm on the road somewhere, and the device doesn't recognize someone in my office (those have all been legitimate entries so far, not burglars).
The original Canary feeds temperature and relative humidity to the cell phone app, which is one of the reasons why the Wendlands chose it. We, too, have a dog that we leave in our Class B from time to time, so the temperature feed to the cell phone is extremely important.
Canary just launched a related battery-operated product called the Flex, which is intended for outdoor use. You might assume that a battery-operated version would be ideal for Class B use, but the Flex does not include temperature feeds.