I could not find any examples of this usage, but what I'm basically asking is whether or not this is possible:
Rather than being mad, I am sad
Is this a legitimate way of using より?
It is a legitimate way of using より, but not a legitimate way of using 怒る ;) (If I understand you correctly, that is.)
For 怒る, you want to express a state, which you should do with the ~ている form. That is,
(Inserting the explanatory ん makes it sound a little better...)
より works best though, if you use two constructions, which are the same, e.g.
Other variations on the same theme: