Along these lines, it'd be nice to have a 'net assets value' indication - essentially, the amount of cash you'd make right now if you were to sell all of your resources (warning: numerical integration probably required!  unless your demand curves are integrable, in which case, good job!)

Ahhh, that might explain why I get bought out just as I'm selling a huge chunk of resources to generate enough cash to perform a buyout myself.  If the net value of resources is calculated in such a way that it inflates your actual net value, then selling resources can quickly devalue your company.  Further amplifying that effect is that Soren J. mentioned that cash has a diminishing effect on your stock price.