We have several (ok, many) domains and are focusing on natural search position across several keyword and key terms and keyword clusters under a single theme.

We have a cool tool for checking our domains for best position at search engines (DRT - domain research tool) but we don't have a method for quantifying the results so that we can say, "This month our search score index is 65.6 versus last month's 60.1."

Anyone have a method for rolling up numbers like this?