"i wonder if two could do a duo"
interesting concept
In a haptek window only one could sing,
but in video both could sing alternately with both present and of course in own voice.
I thinking of Nate King Cole and Natalie in song "Unforgetable".
Looking at it, song is 3 and a half minutes which equals about 12 mb video
Interesting idea
But maybe not exciting like "My Guy" video.