How about md5 crypts instead of password in the cookie? That would allow passwords > 8 chars (with a user table change).

md5 may be too CPU expensive; needs to be tested.

An md5 crypt certainly takes more time than a des crypt: one some machine the md5 crypt seems to take 5e-4 second, the des takes 1.3e-5 seconds.

(comments about $3$/NT-hash)

Instead of comparing hashed password in cookie to hash of clear password in database, store the hashed password in the database and the non-salt part of it in the cookie; authenticate cookies via string compare.

Later, unhashed password will be eliminated.

update user edit page to require the previous password in order to change the password

have a real "password reset e-mail" feature