Laurent Tourondel (chef-owner of some great restaurants in NYC and beyond) has a BLT Burger in The Mirage, where you can get kobe beef burgers. http://www.bltburger.com/

Also, Hubert Keller of the very fancy Fleur de Lys in SF and Vegas owns the perpetually mobbed Burger Bar at Mandalay Bay: http://www.mandalaybay.com/dining/burgerbar.aspx

Have fun!

I have had some great burgers @ the Burger Bar. On the walkway between Luxor & MB.

We had a good burger at the Burger Bar. I thought it was overpirced for what you got, though. I was more impressed with their fries than the burger.

Respecting your request for the upscale burger. If you are not from InNout's region; you do not want to miss while you are in Vegas. The double double with grilled onion is gourmet fare from a chain.

Daniel Bouloud in the Wynn.

my husband loved the one at mesa grill

AVOID the grill at Wynn. Terrible

I ate at Burger Bar. Actually the waiter suggested a burger with anchovies or capers or something. It was different and pretty good, but overall, I thought over priced and over rated. Its a different type of cuisine, but we ate at Wolfgang Puck's place and it was delicious. I live in NY, get to go to Manhattan often, and while I'm not a food snob, I have had enough to be a pretty good judge.