Firstly, I am not going to make this mod. I know nothing about the GECK. This is simply a suggestion for anyone who wishes to pick it up.

Has it ever bothered you that the Strip is almost empty? The streets, the casinos, all almost empty. My suggestion is that more generic characters are placed on the Strip and in the casinos, Freeside and possibly North Square to make it feel more populated. Also, put more people in the 'listening area' during Kimball's speech at the Dam. Because ten people is not a crowd.

Yes, I know this would cause framerate issues for some, but for people with a modern and decent system it should work OK.

EDIT: Oh, and if anyone knows a mod that removes the walls between the three bits of the Strip and makes them a single cell, PM me.

It's never empty for me. Bug for you, maybe?

The strip has most of the "life" in the game. That is one of the reasons each section is blocked off with loads; to unload NPCs from the previous section so it doesn't bog down the system.

What I meant was almost empty: The cell with Ultra-Luxe and The Tops only has:
-Two securitrons.
-Three NCR Troopers.
-Billy Knight.
-The Phebuses.
-The Street Vendor.

Not much life? Half of those people are generic and three more people leave once you've done their Quest. The Street Vendor is probably pretty lonely by now.

And the casinos rarely have more than fifteen people in the entire building.

Give it time. There will eventually be some mods to place more NPCs into the game. I am planning a trip for El Nada to visit NV at some point.

http://www.newvegasnexus.com/downloads/file.php?id=35369

More random people waltzing around wouldn't feel very immersive though.
I hope a mod like better cities for Oblivion shows up for NV though. That mod really made the cities way more beautiful and cinematic.
It did things like expanding areas, changing city layouts, adding clutter etc.