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.
Perhaps of Interest...
downloaded 42s ago
Append the track number of selected tracks to Song Name
downloaded 5m 16s ago
Copy Artist to Album Artist of selected tracks
downloaded 8m 43s ago
Two scripts copy text from clipboard to current or single selected track's lyrics tag
downloaded 12m 2s ago
Display, create text file listing info of dead tracks
downloaded 18m 53s ago
Remove iTunes tracks disassociated from files
downloaded 21m 15s ago
Apply selected CD's CD Text to its disc and track tags