For reference, here is what WMP12 looks like when playing video. Note that all the control can be autohide.
@nevcairiel Thank you for the info. Looks like it's really hopeless.
Still, I think if someone are going to do it, I think replacing the button, seekbar, etc. with Windows' UI is the way to go. Any "unique" GUI will alienate at least half the MPC-HC users.