I wonder if you could evaluate a page using your own algorithm, which is probably not gamed as much as Google's (because who cares about your search engine?) T

I wonder if you could evaluate a page using your own algorithm, which is probably not gamed as much as Google's (because who cares about your search engine?) Then, check Google's ranking of the page. If it is much higher than it seems the page should be, assume the page is being SEO hyper-optimized and penalize the page proportionately. Basically, using the variance between Google's model and your model as an indicator of an SEO spam page.