Since the following isn't possible to do perfectly by modders, this is posted here as an official request to Beth/Obsidian (instead of the modding forum) for all gaming platforms as a DLC.
First thing is first to avoid confusion.. This request is for instanced multiplayer contact. This is not an MMO type of multiplayer request, nor does it involve other players walking into your world and doing quests with you - 100% no. Keeping in mind DLC is optional to download. If you do not download the DLC, you won't see it existing. That means it does not affect the single player environment in any way, so the player must, for example visit a special dungeon or NPC to interact with the proposed DLC content
Just to clear up the big question that most people will ask (Is it possible?) - Multiplayer in a Bethesda game engine has been proven to work to an extent by a modder in the Oblivion community (Look it up on the net if you're keen to know more), so it is possible to include another player in the same game world as you. If he can do it, why can't Beth/Obsidian eh? So yeah, the devs should actually give us the opportunity to experience Fallout with another player.
Now, before you jump the gun and say "Fallout is a single player intended game only, multiplayer is pointless", when you make multiplayer an instanced arena death match type game in something such as the NPC combat arena (Name removed in case of spoiler), you have the reason for it working really well in the game world. Hell, throw in some random fallout fauna into the mix during a round just to make combat more interesting, and you've got something fun to come back to.
In my opinion, matchmaking with others could be determined by a players stats, and perks. I believe players stats and perks choices really influence in creating a unique twist with death match - Not everyone is the same. In saying that though, player single player stats, and perks should probably not be modified by multiplayer progress, as that would defeat the purpose of playing the game properly. For example, winning a game would not level your game stats up. Think I'm wrong? I'm honestly happy to hear why you'd think so.
If the devs find it difficult to make the exact character you play as picture perfect to how you look like geometrically, the problem can be tackled in 2 ways that I can think of...
1 - Just spawn the player in as a random preset model that the engine can deal with perhaps. Maybe different days of the week in the game could offer different themed models for that specific day (Gangs, factions, and mutants for example), and the more games played or won by someone could unlock higher ranked types within those gangs, factions, and mutants for that person playing.
2- When you enter the arena set up area, you must choose who you want to represent when you fight. Once you choose to fight for one specific gang, major faction, or the super mutants, you will only be outfitted as a model within the gang/faction/mutant group and your model will change as you progress based on your success, or productivity. Or you could keep the model you prefer, just saying. If you don't like the group you're representing, change it to another - simple as that... Should changing your progress in some way?
Further to that, in my opinion just to make it worthwhile, because ammo in Fallout is, players ammo count maybe isn't affected when you go in and out of the instance - Meaning if you come in with 249 ammo with your rifle to an instance, you go back out with 249 ammo with your rifle. Comments?
Well, I appreciate anyone who has read this rant completely, so just a reminder that if you want to put in your two cents, if you completely hate this idea, or add your own idea in this thread for multiplayer in New Vegas, please do so, you are most welcome.
Thanks heaps.