Well, I'll be doing a gamerip of JJ2 soon, a gamerip being exactly what you want; properly looped and faded MP3s of all the music. I've already done the tracklist but I haven't timed everything yet;

01 - Jazz Intro*
02 - Jazz Jackrabbit 2
03 - Jazz Castle
04 - Carrotus
05 - LabRat
06 - Sugar Rush!
07 - Colonius
08 - Medivo**
09 - Hippie Heaven
10 - Beach Bunny!
11 - Marinated Rabbit
12 - Boss -Alex B.-***
13 - Diamondus Remix
14 - Tubelectric Remix
15 - Medival Jam
16 - Boss -Robert A.-
17 - Jungle Fevah 2.0
18 - Hell Freezes Over
19 - Dark Groove (Part 1)
20 - Jazz be Damned
21 - Finale*
22 - FastTrack
23 - Frolick Lane
24 - Jazz Belmont
25 - Streetwize
26 - White Hare
27 - Pull Back The Bass
28 - Level Complete****,***
--BONUS TRACKS--
29 - Episode Select (Unused)
30 - JAZ30 (Unused)

* No loop
** Technically not unused since it appears in the OEM version
*** Needs to be manually ripped from the game
**** All three level complete jingles one after another

I did all that from memory so I probably missed some stuff.