Get a dropdown login like WPMU

Hi,

I really want a dropdown or modal login on my multisite instead of the boring standard login screen. I have checked this thread out: https://premium.wpmudev.org/forums/topic/how-can-i-add-a-login-drop-down-like-on-wpmu
and found out i may have to use this: http://red-team-design.com/simple-and-effective-dropdown-login-box/
but how is it possible to implement this, into my site? I can't figure it out.

Note: It is not possible to use some modal login plugin, because i have a mu-plugin that redirects the users to their own blog, when they log in on the mainsite - and it does not work with other login plugins!