I must point out that I have no previous experience in neither open source nor firefox extension development, so I basically just packed everything back to an xpi file. All props goes to duz however, and he can decide whether to use this code or maybe do something based on it to his hearts content.http://drop.io/nzbdstatusMod
It works by retrieving category details with Xpath DOM traversal and setting up rules based on sabnzbdplus's categories for each index site individually, based on what the index sites offer. Since this is a bit of a flaky approach it means that the sorting will not work if the sites alter the presentation of the information (to a certain extent anyway). I'm not happy about the hard coded rules array, but this was initially intended just for me and a friend, so the approach was pragmatic.