Hmmm. Well, you certainly have quite the list already! Everyone has their own taste, but I like these:
1. M writes "Whore" on part of my body (ass, tits). Washable markers are great for this
2. Similar, but how about a sign that states your offense that you must wear for X time
3. A photo of you being punished (corner time, in place for a spanking, etc) that could be put on your PC and displayed as wallpaper, or if you have a photo printer, printed out and put on the fridge.
4. This is something I'm not sure if I could do, but the idea appeals to me: A photo of yourself as in #3, but not showing anything identifiable (face, etc) that would be posted on this forum.
5. Having to ASK for punishment is almost a punishment in itself........M sometimes makes me beg for it. He's been known to make me keep at it for over half an hour before giving in and meting it out.
6. Ooh, just remembered: this one also appeals to me, though not sure if I could really do it. Having liquid soap poured into your mouth for a verbal offense (talking back, etc) and held there for x minutes before being allowed to spit it out.