BBC Radio 4 recently broadcasted a new radio play adaptation of "Pinocchio". This marked the first time a radio production was mixed object based with tools by IOSONO. The mixing wasn't done channel based, but object based, positioning the audio sources independently of the speaker setup and later generating different output formats from a single mix.
The BBC R&D blog
gives some insight on the mixing process, check it out if you like! A 5.1 mix of the play is also offered for download on the site.