@ Martin ...
Wonder if your situation is different: Rackspace Cloud Services via hosting provider.
"There is not currently a way to cap cpu cycles or disk space, so if you are concerned about going over the limit you will need to monitor your cpu cycles closely. Your compute cycle statistics are available to you in near real time from your control panel. In addition we are happy to assist you in locating any problems causing you to use excessive cycles, just submit a support ticket through our Help Desk."
'spirit of sharing', Ken