[Radoye]

That there is a Me-262A-2a/U2 dedicated bomber variant with a bombardier in prone position in the nose replacing the guns. It's a real variant, built and tested as a prototype.

I am unaware of this kind of a Mistel combo with the lower portion also being a Me-262, as far as i know the proposal was to use a Ju-287 jet bomber but it was never actually used in that configuration, not even for testing purposes.

There was however a project of a purpose built flying bomb, the Arado E-377a, which was to be used in a Mistel combo. At a first glance it looked a bit similar to the 262:

http://www.luft46.com/armament/are377.html

But this was supposed to be used with a He-162.