What is the maximum allowed password complexity in Multibit What are the maximum number of characters allowed in a Multibit password, and which characters are allowed?

Since I use Keepass as a password manager, my usual practice is to generate passwords with the maximum allowed complexity.
Internally the password is a byte array (made from the unicode representation of the characters).

The only hard limit is the amount of memory the bytes take up in the MultiBit process. If you had a password of a million characters I think it would work but a billion characters would probably break it.