Okay, what about the Infiniti M35h? Maybe not as fuel efficient as some of the others but definitely hits the luxury area you are looking for.
Oh right! I did drive one of those, but afterwards dismissed it.
It just doesn't feel anywhere near as polished as the GS...or other luxury hybrids for that matter. It's a bit hard to explain. It's less seamless is maybe a better way.
A car that DID surprise me and that I DID like (lots) was the Acura RLX Sport Hybrid. But they are well above my budget...and MPG is less than hoped for. Beyond that....I really liked it! Styling was a bit staid though. Handling was very good...powertrain very robust.