Searched high and low for a command to get CPU usage on the internet to no avail. From a DOS command prompt (Windows server 2003) CPU usage for all nodes:

 WMIC CPU GET LoadPercentage 

SNMP was my other alternative, but not all deployments would have this service.

This does not aggregate the values, nor does it easily feed into a batch file. For that I use a FOR loop.

 FOR /F "delims= " %%i in ('WMIC CPU GET LoadPercentage') do @echo %%i