Well, after countless more instances of making myself comfortable on the couch, turning on the TV and choosing a nice movie only to be greeted with a "path not found" message because fucking automount doesn't work, I finally gave up on it. Great job, Apple. (They broke it with Lion.)
Instead, I planned to use a cronjob to keep my NAS connected. That's crude as hell, but what can I do?
However, several sourced recommend to use launchd instead, and so I did. At least for my use case, it's pretty much the same. I wrote a small shell script to mount my NAS, and also a launchd job definition, which is just a .plist file containing the schedule of the job and the path of the script to execute. I saved the job in ~/Library/LaunchAgents, so OS X loads it when the user logs in. I've configured it to mount my NAS hourly (if it isn't already mounted), and also immediately after logging in. Works great.
In case anyone is interested in launchd,
launchd.info is an excellent resource.