The standard Perl hash, the size of the key plus data is limited to 1008 bytes. Is this enough for you?

When I use bigger data, I use DBM::Deep. I tie it to a file but it's darn fast and has worked fine on multiple applications for me. I believe the hash data size is only limited by your hardware and OS, same for the max file size.

Other people have tied DBD::SQLite into a hash also.

Max data size when you tie BerkeleyDB to a hash is 1 billion bytes.