I know the described behavior (update the default search engine each program start after few seconds), as long as you don't have changed your /etc/hosts file (see step 3 of my original post).

However, your workaround sounds interesting. The question is, if your 8_all file gets updated when opera changes the defaults on their servers... (I suppose, there is some kind of a ID / time stamp involved?!)

Concerning the favicon: I didn't bothered about that myself, so I can't give you a solution. But you might find some more information about the skin-vga.rsc file format and embedded bitmaps on this site.