The Large File summit has been in 1995 and any recent OS should support files > 2 GB - 2 bytes.
LFS unified programming interface to deal with large files, but they couldn't possibly require that every single file systems shall support large files, could they?
Currently neither Linux nor Solaris do support multi extent files (files > 4 GB) with ISO-9660.
Linux actually supports multi-extent files. You indeed can't break 2GB limit [trivially fixed actually], but you can have multi-extent files since a long while ago. But one way or another! World does not consist of Solaris 11 and Linux 2.6.20 and most importantly *never* will! In addition as far as 2GB limit goes there is a whole lot of isofs implementations, which would break on it for one reason or another. IRIX for example "breaks" on 2GB because isofs is accessed by means of user-land NFSv2 and the limit is imposed by the protocol. FreeBSD breaks on 2GB because of improper sign extention (kernel bug). As far as I can see NetBSD would actually work on 32-bit platforms, but not on 64-bit platforms, again because of improper sign extention (kernel bug).
For the above reasons[1] mkisofs[2] should [at the very least] warn about files larger than 2GB or [more appropriate from my point of view] refuse to generate output unless explicitly permitted to do so. A.
[1] world not/never being perfect; [2] a program meant to be used for data *interchange* in imperfect world;