So, the thing about this is that what you're asking for would be a pretty specialized product which means you'll likely be paying a premium price compared to the possibility of getting a deal on two AV receivers from last years product model line-up.
I'd look into splitting (or switching) the source input to two AVRs in each room and see if that meets your needs.
When you say you're looking for a high end amplifier, what specific features are you interested in that mainstream products would not meet?
To directly answer your question though, if you just want to drive a lot of speakers and have a set of pre-outs from your primary AV receiver, maybe you would be interested in a product
like this that can drive the speakers in the "other" room.
But, as I said, if I were you I'd consider adding a switch to switch your input sources between your two AV receivers.