I recently went about replacing the factory lights on my 01 Sierra for the same reasons. I wanted to upgrade to the Denali projector beam lights too. What I ended up doing was finding the OEM part number for the Denali lights and simply doing a search for them that way. It allowed me to cut out the clutter of useless adds that have a bunch of search engine words attached to the add.
What I ended up finding in my situation was OEM lights were an arm and a leg. Used OEM lights were only slightly cheaper than OER units. I said to hell with it and took my chances with the OER units. I figured if I someone wrecks their Denali, they are only going to get OER lights anyway. I'm afraid you might end up with the same situation. Just make sure they are DOT registered/legal. Those will be the better ones. Also, be sure to wax them like the paint. That will help keep them clean and not fade.
Good luck.
Of course, you could also go custom and make your own.
www.rallylights.com has good headlight selections