Very interesting space probe proposals from the ESA
Such as a Venus Entry Probe, Interstellar Heliopause Probe, Jovian Minisat Explorer, and Mercury and Demois sample return missions, the former using solar sails.
You can read the details and get some papers on these proposals here:
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35987