Karnak: I believe in a semi-recent He-177 thread somebody brought a lot of info out about later versions of the He-177 and how it was used in larger numbers for level bombing on the Eastern Front for a while. This would be after much of the engine problems were solved (but, if I recall the discussion correctly, not all of them solved).
I wouldn't say sat as a target was the only thing it did because the later "fixed" (or "reworked" or whatever you want to call it) variants were much more reliable.
In general I don't want to see it in AH any time soon, but I wouldn't rule it out completely.