Applications :: Safari Remember Username Not Password?

Is there any way to make Safari only remember the username and not the password of a website when using Autofill? I've noticed that Firefox does this and Facebook does this in Safari when disabling "keep me logged in" (maybe a cookie feature?), and this is the exact behaviour I want.

I use 1Password and thats great, but I'd love to just type my password and automatically have the username show, and not keep having to type in my 1Password keychain's password.