t-scan: A software for complexity analysis of Dutch texts.
The automatic English translation is available.
There is a log in screen at http://languagelink.let.uu.nl/tscan/login/?next=/tscan/app/ but no register link, so I guess one has to contact the researchers / developers in order to examine the application with realistic examples.
The application seems to be inspired by the CohMetrix system: Coh-Metrix calculates the coherence of texts on a wide range of measures. It replaces common readability formulas by applying the latest in computational linguistics and linking this to the latest research in psycholinguistics.