FaceTime video voicemail, where are you?

It seems like such an obvious thing to leave a video message if someone isn't available for a FaceTime call. I'm sure Apple considered it, but the feature doesn't exist. How come? I'm not a big FaceTime user. In fact, I only use it with my girlfriend but I'm sure she'd like to receive a little video message sometimes. </mush> Yes, I could record a video of myself and iMessage it to her, but that's not the same and I don't want a bunch a videos of myself on my phone that I have to delete. Doesn't this seem like an option that should be built in?