OK. This is my second post tonight that will go against the tide.
IGNORE the gas grill.
If you are willing, or rather the wife is willing, to spend $500, then PLEASE go for a side firebox smoking wood-fired grill/smoker.
Brinkmann makes several very reasonably priced side-box smoker/grills of good quality, and they cannot be beat for versatility.
You can use charcoal or wood, and add fuel to the fire without getting ash on the meat, and with FLAVOR added to the meat.
Temperature is easier to control, as is the volume of smoke, and you can cook a piece of meat much more slowly, retaining the moisture. Placing a reservoir of water in the cooking chamber is more easily accomplished, as well.
Brinkmann is NOT the only ones to make a side-box smoker, buddy. Look around, and for the price some of these bland-flavored gas boys are asking, you can get yourself an armor-plated meat machine.
PLEASE look into a side-box smoker, if you are already willing to spend that kind of money. You'll make your money back in one weekend at the church ice cream social!