So I'm thinking of making a vault-boy character.

But since he's got his hands in everything... lol... how should I make such a character?

Armored vault 13 jumpsuit/leather armor without classic pack

10mm pistol -> 10mm smg -> lmg

varmint rifle -> hunting rifle -> amr

grenade rifle -> missile launcher -> fat man

That's what Vault Boy is to me, at least.

Always wear Vault clothing, for one. Also, living in a Vault, he probably didn't have access to many EW, so Guns should be your main combat skill. Other than that, its all up to your imagination.

I'd say....

Slightly pale skin, blonde 'tunnel snake' hair, tag your EW so your starter pistol is a Laser Pistol, wear the Vault 21 suit, and if you ever go through V34, use Vault Security Armor.

He was a possible squad member in Fallout: Tactics, http://fallout.wikia.com/wiki/PIPBoy_%28character%29

Vault clothing and the occassional BoS power armor, and NCR black armor. He has donned those a few times.

I think go with the smooth wave hairstyle