I'm working on an alternate start mod (plus housing), and can't seem to figure this out for the life of me. I "know" mods like Body Control/FEM are able to change actor appearance entirely with scripts, but I don't see any relevant functions in either the http://mod.gib.me/fonv/functions.html or http://fose.silverlock.org/fose_command_doc.html other than cloning facegen and race data from another NPC. There doesn't even seem to be a form list of player races, face presets or hairstyles that I can find. I take it then that BodyControl/FEM work with dummy items that specify specific models for their base? And the game manages its own race/etc lists that not even NVSE can get me access to?

I was hoping to completely replace the hard-coded appearance menu with an in-game selection that would be compatible for instance with Children of the Wasteland type mods (the normal one bugs out if you try to rotate it, because the height of the camera is pre-set). I fully expected to have to wait for NVSE to do this, and figured I might have to use the hard-coded menu to offer finer facegen control if the player wants it, but not even being able to get a list of installed races/face presets is somewhat unexpected.

To make matters worse, FNV also seems to crash if you give the player a pipboy without doing ShowRaceMenu first, even though third person shows the player does have a default appearance. I'd really like to do everything as dynamically as possible, but if I can't work around this pipboy crash it seems the whole matter is moot anyway.

Just in case anyone comes across this problem, I've finally figured it out properly. It's not that you have to do ShowRaceMenu first. The crash is caused by the pipboy processing in GameMode before ResetPipBoyManager is called. What you have to do is both "player.equipitem pipboy" and "ResetPipBoyManager" when the player is in a MenuMode such as the dialogues where FO3 and FNV give it to you normally.

If there's anyone this is not news to, I wish they had responded to this post. There's nothing worse than a crash that's caused by stepping through a sequence one step at a time X_X

The ones we have are:
http://geck.gamesas.com/index.php/MatchRace
http://geck.gamesas.com/index.php/MatchFaceGeometry

Yep, those are what I was talking about when I said cloning race and facegen data. It would have been nice to be able to modify the facegen values directly, but it's hardly necessary. What I have more concerns about now is hair and eyes. How are these implemented? Are they or can they be replicated with equipment?

Sorry, missed that line.
Hair and eyes are slotless things, defined under Character->Hair/Eyes/Headparts, and specified per race under Character->Race. You can't really replace them with clothing, as wearing an item using the Hair or Hatband slot will make hair switch to its 'Hat hair' mesh which is smaller, but probably not small enough to make wigs feasible (unless you want to set the default hair to be bald).

So it's impossible to change hair and eyes with scripts? Even with NVSE when it's out?