Did a very cursory search, didn't find anything professional. Here's an amateur meta-analysis that attempts to tackle it: http://scienceofmom.com/2011/12/22/fruits-vs-veggies-are-they-nutritionally-equivalent/#more-724 Methodology seems legit to me, the data is from a reliable source, and it also more or less conforms to what I'd intuitively expect. Do keep in mind that this is nutrient density per weight, not nutrient density per calorie. How much of a food you can eat will depend more on the latter, and I'm guessing fruits have more calorie per gram then veggies (making vegetables even more important)

It (at least, the abstract, the rest is paywalled) deals with "vegetables and fruit" as a single category, not a disjoint union of two. I notice that in the list of subject classifications for the article, one of the classes is "fruit and vegetables". The everyday distinction between the two is not relevant to nutrition, and there is no scientific distinction. In the technical discourse of the laboratory, some plant organs are called "fruits", "nuts", or various other things, but none are called "vegetables". The questions to ask are about which fruits and vegetables contain which nutrients.