Interesting idea. I do like the asymmetry of signing depending on the type of AP. Signed negs would have more impact than unsigned ones, and unsigned positives would have less effect than anonymous ones.... There's just one problem.
The positive AP issue won't be workable. People will just put in something which identifies them but does not contain their name in a plain manner. They're either put in (example) "V o r l i n" or "--Vrln" or "My Sig Here" or "URL to my profile here" or something. It is certainly possible to penalize unsigned, but not possible to penalize signed ones, given the way that you have to match things.
The negative signing scheme sounds good, but the positive one is unenforceable.
If this DOES get implemented, however, I feel it would be worthwhile to add in a few features. Such as being able to assign less than full amount, and also to have the system do signing in such a way that a user cannot spoof a negative by another user by simply typing in their name.
