The chart on the right, provided by Michael O'Hare of the UC Berkeley Transportation Sustainability Research Center, doesn't quite do this, since there are many dimensions to boondogglishness. However, it does measure one aspect of boondogglishness: whether corn ethanol actually provides any green benefits. As you can see, the answer is "it depends on how you make it."
The thing I've labeled Corn 1, for example is "Coal-fired ethanol production with cogenerated electricity." Basically, it sucks, producing nearly as much total greenhouse gas emissions as gasoline. Other types of corn ethanol are better, the best being "Biomass-powered ethanol production," which clocks in at about half the GHG production of gasoline. Switchgrass ethanol, the holy grail of the ethanol community, is even better.
There's more to corn ethanol than this, of course, since ramping up corn production requires big federal subsidies (bad), drives up the price of food (also bad), and demands intensive nitrogen fertilization that produces greenhouse gases of its own (yet badder still). A complete boondogglishness index would take that and more into account. But if it's basic greenness you're interested in, this chart tells the ethanol story pretty well.