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.)
Download any or all available subscribed Podcast episodes not yet downloaded
Capitalize the first letter of each word in selected track names
Display, create text file listing info of dead tracks
Exports and then re-imports selected tracks' artwork
Assists with finding truncated iTunes Match tracks
Set choice of various number tags of selected tracks incrementally