Hello Nick,
I have been using a Dedicated Micros ECO 4 machine. The only thing I am not sure about is that it will start recording when motion is detected. But you can programme it to record an event upon motion detection and store it seperately fron all the footage where nothing happens. When you log on you select the cameras and just view any events that have occured. This unit will also e mail you upon any events occuring but you might get fed up with this as it is surprising what can cause an event trigger. My view of this machine is that it is a very capable robust machine with plenty of info available from the Dedicated Micros web site. You can go on to their site & download all the info for this machine. It is also has very good networking facilities. The best part is that you can pick up a great second hand bargain from e bay.
Hope this helps
Mick