Imagine a 401(k) where there’s no investment menu of stock funds. Instead, you get to make one that aligns with your values.You could begin by knocking out oil drillers or gun manufacturers, or subtracting companies one by one depending on which ones have crossed you (or the world) lately. And when you’re done, you — and not a mutual fund — own individual pieces of every other security that you’re not beefing with, whether personally or as a citizen of the world.Some of the biggest names on Wall Street can conjure up this tantalizing prospect, which is …