Email triggering on custom or build in metrics

It would be extremely useful to be able to trigger emails when a metric matches a specific rule.

e.g.
For a C build i measure number of compiler warnings.
I would like to trigger an email when the number of warnings have increased

I build a binary for an embedded platform and measure the static RAM usage from the map file that the image would use.
I would like to trigger on a maximum value e.g. 128K to let the user know that although everything build and the unit tests passed it will never fit on the embedded device.

So in a nutshell i can think of
<rule delta="increase" />
<rule delta="decrease" />
<rule min="10" />
<rule max="100" />
<rule max="100"  min="10"/>

This could be added to the bit of code that parses the teamcity-info.xml ?