I came accross Bugsnag, very nice tool... Is there a way to connect this to FuelPHP? There is a monolog-bugsnag package... https://github.com/meadsteve/MonoSnag/
Easiest is probably to overload Log::initialize() (since 1.8/dev).
static::$monolog contains the Logger instance, you can add whatever handler you want to it. If your overloaded method calls the parent, it will add Fuel's own handler too, so you retain the current log files.