I'm happy to say I've made this mod. Not exactly like I originally intended, but good enough http://www.nexusmods.com/fallout4/mods/18946/
WARNING: CONTAINS FALLOUT 4 PLOT SPOILERS - for character generation only:
I wanted to write this down so I don't forget it.
I claim no copyright of this idea, if you want to create it go nuts. I probably won't.
- Before the bathroom mirror scene, pick a house in the pre-war neighborhood of Sanctuary - either the vanilla house or another one. (This could just be done in a pop-up menu for simplicity)
- If you pick the vanilla house, story progression follows the default vanilla path
If you pick the other house:
- You get a bathroom mirror scene with a single character. You create your character in front of the mirror.
- The Vault Tec rep comes to your door. You can choose to be ex-military and get free entrance into the vault, or be a leading scientist, businessperson, winner of a raffle, whatever, such that you get entrance into the vault. (this could be hacked together from the vault tec rep's existing dialogue lines pretty easy)
- Bombs are dropping. Run up the hill, go to the vault, get frozen in the pod across from the baby.
- Watch the baby get snatched, you are "the backup."
- Unfreeze. Wife/husband of person with baby is dead in another pod.
- "Hmm, I wonder what happened to that baby..." Main quest starts (would require some editing of the pip-boy text etc. so that it's not *your* baby anymore.
- Codsworth could be moved to a different house in the neighborhood.
This is my best idea so far for allowing the player to play as someone besides a concerned parent, without having to *totally* overhaul the game.
The hardest part is that to be consistent throughout the game, it would require removal or editing of some dialogue options, primarily in the main quest (e.g. "where's my baby", "my son" etc.) and even some lines from other characters who refer to the boy/son/Shaun character as the player's offspring.
Removing those speech options wouldn't be hard to do with a few dialogue conditions that check to see what starting story you picked, and then disabling those options if you did pick them. However, that's assuming the GECK for FO4 allows you to have less than 4 dialog options, and functions roughly the same way as the Skyrim CK (allowing conditions on dialog options).
Editing those speech options presents a much more difficult problem. All those times where the player's voice refers to "my son" or "my baby" would have to change to "the boy" or "the baby". Also, finding a missing child is important, but probably wouldn't warrant the same level of emotion as it would for your own child.
Maybe this is impossible, I don't know. It seems like it could be done though.
Anyone else have alternate start ideas that are actually feasible?
Everything I can think of for alternate start (e.g. similar Skyrim's Live Another Life mod) still requires the same significant modifications to the main quest dialog. On the other hand, once those main quest modifications are made, alternate start options are basically limitless.