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.
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downloaded 1m 43s ago
Remove iTunes tracks disassociated from files
downloaded 2m 53s ago
Change selected tracks' Start Time or Stop Time by user-entered seconds
downloaded 3m 5s ago
Apply selected CD's CD Text to its disc and track tags
downloaded 3m 56s ago
Copy selected CD's CD Text to the clipboard
downloaded 10m 11s ago
Perform search-and-replace on text in your choice of tags
downloaded 13m 31s ago
Delete characters from the beginning or ending of selected tracks' name, artist, album, comments, composer, or show tags