Making MythTV email me with errors

I just happened to log into MythWeb and noticed that I had an error:
Last mythfilldatabase run started on 2010-09-02 03:49 and ended on 2010-09-02 03:49. FAILED: xmltv returned error code 512.
There's guide data until 2010-09-08 00:50 (6 days).

A quick Google suggests that this should be easy to fix (although I have no idea why it failed after months with no issues), but we are going away and I could easily have been caught out.

Is there a way (a plugin, a script somebody has written etc) to have MythTV email errors that are likely to require intervention like:
* this one (a guide update failure);
* a failed recording;
* low space or, if "AutoExpire instead of delete" is turned on, very few remaining deleted recordings to expire; or
* a failure of mythconverg_backup.pl.

I clearly wouldn't want to be emailed with every entry in the logs (I get hundreds about reference frames etc).