Hot diggity! Got curious and did a test. Zeke - yes, it's indeed possible to make a .pbo addon with the songs you want available all the time without messing with mission-specific description.ext entries.
Here's what I did:
[1] Created an empty folder somewhere on my HD that I named "muzak" (the name of my addon to-be)
[2] In that folder, I made a subfolder called "music"
[3] Put a couple of .ogg songs into the music folder
[4] Created the following config.cpp in the "muzak" folder:
// Some defines (borrowed from BIS' own commented .cpp-files)
#define true 1
#define false 0
// type scope
// used for show entry
#define private 0Â Â Â Â Â Â //! item is never visible
#define protected 1Â Â Â Â Â Â //! "advanced designer" switch must be activated to use it
#define public 2Â Â Â Â Â Â //! anyone can see/use it
#define ReadAndWrite 0Â Â Â //! any modifications enabled
#define ReadAndCreate 1Â Â Â //! only adding new class members is allowed
#define ReadOnly 2Â Â Â Â Â Â //! no modifications enabled
#define ReadOnlyVerified 3Â Â Â //! no modifications enabled, CRC test applied
class CfgPatches {
   class muzak {
      units[] = {};
      weapons[] = {};
   };
};
class CfgMusic {
   access = ReadAndCreate;
   tracks[] = {finawar,model};
   class finawar {
      name = "I fought in a war";
      sound[] = {"\muzak\music\finawar.ogg", db+0, 1.0};
   };
   class model {
      name = "The model";
      sound[] = {"\muzak\music\themodel.ogg", db+0, 1.0};
   };
};
Then I packed all that up in a muzak.pbo addon using Amalfi's MakePBO (Avaliable here on OFPEC) and
put that muzak.pbo in the AddOns folder.
After starting OFP, the two songs ("I fought in a war" and "The model") are available in the Music part
of the effects dialog for a trigger in the mission editor.
Some notes:
- The folder is named "muzak" and in the CfgPatches there's a corresponding "class muzak".
- Note the paths to the songs: "\addon-name\sub-folder\song-name.ogg"
- The "access = ReadAndCreate" is from the BIS config.bin. Dunno if it's strictly necessary
- Actually, you don't have to have a separate "music" subfolder. If you don't, the paths in the CfgMusic will have to change accordingly, of course.
- I don't know from which version of OFP this will work (using 1.91 here), so I didn't add a "requiredVersion" property to the CfgPatches part.
Comments/additions/gotchas/fixes/others welcome!
I can see the sites now... "The 60's mod", "Grunge Rock Mod '91", "OFP Disco Mod" ;D