A file is just a bunch of bits. The way it is arranged in memory has nothing to do with the newline character. Any limits are arbitrarily imposed by outside applications. Perl, to my knowledge, would have no reason to care. Perl does not specifically care about lines either, they are only a string of data ended with whatever character is in $/. Scalar variables are limited only by memory, and have no problem with reading an entire file if you change $/. Just my two cents.

When's the last time you used duct tape on a duct? --Larry Wall