Very cool. I wondered how exceptions would work. I like how it puts the traceback in there. This is WAY more useful than the current cron method.
I have a web2py app generating a report every morning that takes a few minutes to run, I had to write a module for it, then a bootstrap file for it, then add it to cron, along with a whole bunch of error catching and reporting code because when a cron task fails, it fails silently unless you know where it keeps the log file. This new approach is much better.