Join Together v7.2.0
Join Together will create and export a single AAC or ALAC audio file from the audio data of tracks dragged from iTunes or files dragged from the Finder.
This latest version includes fixes for some memory management issues in Mavericks and later. It will work under the Yosemite beta with iTunes 12, but observe the usual caveats about pre-release beta software.
Join Together is $5.00; this version is a free update for registered users of v7.0 and later. More information and download is here.