Someone finally managed to extract the .pak files data... unfortunately Cryteks seems to think this is a bad thing so his thread got closed... its quite possibly against the EULA ?

look here:
http://www.crymod.com/thread.php?threadid=67664

and here for some cool hd mod:

http://www.crymod.com/thread.php?threadid=67644&threadview=0&hilight=&hilightuser=0&page=1