First post from a VERY satisfied user!
What I'm trying to do concerns the situation where we have, for example, a live album which should play without gaps between each track. There's a method to do this on iTunes, but I haven't seen any equivalent on mp3Tag. Is there a way to do it that I'm not seeing?
This is not a function of mp3tag. Any lossless formats by design will playback gapless from track to track. There is some ability for this with mp3 as well, but it is dependent on your ripping software using the correct codec.
Search for crossfading software, dj software Old Mediaarchive/Winamp can do that too.
mp3tag does not deal with audio content in any way.