funny you should ask, nvidia released an update for system tools, and i just found that it allows you to monitor GPU load/framebuffer usage
clicky its a big old download, but theres an awful lot in there. look under start menu > all programs > nvidia corparation > nvidia system monitor, navigate to the GPU section and its in there

hopefully it wont be too long until someone makes a plugin for rivatuner,i have a sidebar gadget that reads the system monitor values, and it would be so convenient. theres already one for ATi cards so it could happen
