Sadly No. Nobody has been able to figure out how to Re Pack these files yet there are a handful of people out there that should know how to do it in theory but none seem interested in it not even for money.
1) NTAuthority-Creator of Alter IW net who before the recent law suit against him had reverse engineered BO2 in order to add it to the list of games on the site.
[I have attempted several times to contact him by many means no response yet.]
2)Tom Crowley-Creator of several mod tools including the first BO2 IPAK extractor he should know how to re pack them.
[Last I spoke with him he said he was planning on working on it but never got around to it and haven't herd from him since]
3) Tekno MW3 Crew-Anyone who can alter the game maps, and such should be able to repack these files.
[I have not reached out to them as of yet]
4) @kokole, @ipaddie- The two creators of the custom skybox mod in MW3 has been working on a re packer but far as I know have failed to do so.
5) @master131- I know he made an IPAK extractor of his own, and a fast file viewer but has not figured out how to repack them yet.
6) @Archangel-I remember he was into texture modding in MW3 may be able to help.
7) Craig87- Admin for Texture Hacks website has tried to re pack these files as well but has failed.
Honestly I feel we need to start up a project to get this done having things like custom gun skins, Squad member costumes, lobby backgrounds, and sky mods along with a texture hack to color players and surfaces would be great thing to have back in the new games it helps a lot for some people, not just for playing better but for their graphics card and how the game runs in general less your PC has to do the better. I am pretty sure that CRYSIS 2 used .PAK files? Cant we use similar ways to crack GHOSTS and BO2?
FreeFileViewer can open the .pak files I can see the code inside, and I was right the crysis games use .pak as well for texture packing and there is a texture hack like MW2 out for crysis 2 maybe there is hope Hope I helped in some way miss custom textures without them the game seems bland to me.