Sure, iTunes can join tracks, but only if they're consecutive CD tracks, and you haven't imported them. This script allows you to join any two (or more) MP3 tracks (repeat: MP3 tracks only), provided that they are the same format and bitrate.
Also see Join Together, an application that will join any type of files.
(Note: In order to launch this PowerPC-era script on an Intel machine, it must first be opened and then saved using AppleScript Editor, which is located in your /Applications/Utilities/ folder. More information is here.)
Set iTunes to play within 24 hour period
Swap the name with the artist of selected tracks
Locates pairs of track entries pointing to the same file
Rename selected tracks' Song Names with their filenames (minus extension)
Correct song titles listed as "Artist - Song Name"
Open the single selected track in in QTP7 and open QT's A/V Control window