Before iMovies has been upgraded to version 11 from version 10, it was possible to import projects from the mobile version of iMovie (.imoviemobile) to the OS X version and produce .imovieproject file. Unfortunately, such imoviemobile to imovieproject conversion does not to work anymore and there are no news whenever this functionality comes back in future versions.
Open IMOVIEMOBILE file Open IMOVIEPROJECT file