I don't think it's "impossible" per-se to build a Hybrid engine from a 2ZZ head/1ZZ block, but it wouldn't just bolt right together like the Honda guys can do, you would need some serious fabrication and custom adaptors to get a 2ZZ head to mate to a 1ZZ block, or any other block for that matter. you have to worry about clearances, oil passages lining up properly, etc. If it was sucessfuly done, I would've heard about it in the forums by now. And even if you could do it, you would have to change things so much that it would pretty much be pointless by the time you're done.
You can take a 1ZZ crank, and use it in the 2ZZ block to stroke the motor, that's sort of a hybrid setup, but you just can't piece together toyota engines like you can with other engine makes.