It took longer than I anticipated, but I am happy that I can finally present the first draft of my list of MIR data sets.
I decided for a table with a very minimalistic description; obviously I left out a lot of useful info, but I hope that this can give at least an overview and starting point.
Obviously this is work in progress, but at least for now, the links should all be functional and the table is as complete as I could manage. Please let me know if I can add a new data set or if my description is wrong.
edit (May 31, 2014): updated link