Playing with myself, sort of
kdenlive 0.7.7 on fedora 14
I'm not sure if I did that in a clever way...
I used a composite transition (wipe file: linear_x) and kept it stuck at about half opacity. Then increased a little "wipe softness" to hide the line.
Near the end the guitar-me disappears, that was unintentional... I found kdenlive 0.7.7 on a multicore a little buggy, I'm waiting for rpmfusion to release newer packages....
(wink wink, nudge nudge)
(but don't take that wrong, I'm deeply in love with Kdenlive)