Christopher O’Dell, the Grognardling, talks about Charting Alignment, using a mechanism similar to that used to chart honor in Oriental Adventures.
When I’ve considered something like this, I’ve usually found myself treating the various modifiers as ‘encounters’ providing ‘experience points’ toward the alignment. That is, instead of a “+1 to Law” it might count as a “CR 1 encounter for Law”. By treating the alignments something like classes you can actually measure progress toward the alignment (possibly attaching traits or powers to the character), and as the character reaches ‘higher level’ various actions become irrelevant — in order to grow further, greater and greater acts are required.
I originally considered this in a Ravenloft campaign, where it takes greater and greater actions to induce Powers Checks… but a single large action might jump the actor several ‘levels’ at once. Someone who is almost a Dark Lord who kicks a begger in the face is unlikely to cause a Powers Check, but an otherwise innocent who murders his family might find himself catapulted into a position of Dark Power almost immediately.
I never really fleshed this one out much, just kind of noodled with the idea little.