Both Winzip’s and 7-Zip’s AES-256 encryption can use passwords up to 100 characters. I believe ever though the 100 characters well exceed the 256-bit length, a 256-bit hash is generated from those characters.
Although the below generators only generate lengths up to 63 ASCII/64 HEX characters, one can combine one or more keys generated from one or more sites to create a 100 character password for Winzip or 7-Zip.
This one is my favorite and it’s seems to have some good information in it too. It’s also hosted via SSL:
All the sites listed above work great for wireless WPA/WPA2 keys.
At some point I’d like to put together a similar site or page that does up to any length key. Having said that, you can use password managers such a KeePass that have random password generators that allow up to any password length.