Well, April Fools Day is over and things should now be back to normal. To clear up any confusion, here's the complete list of ranks and where they came from:
Not sure how many of these were actually seen. Probably not everyone with a custom graphic posted.
Ayaka, Rio, Shiho, Aoi, Multi, Serio, Tomoko, Remmy, Serika, Kotone and Akari are from To Heart
Sara (TC), Naru (Death), Haruka (LeHah), Mav23 (Mutsumi), mpanty (Suu), Motoko (Phoenix), Shinobu (Dynaco) and Tama [Cadet] are all from Love Hina
Miki (LOAF) is from Marmalade Boy
Miyazawa (Ghost) is from Kareshi Kanojyo no Jijyo. Also known as "Kare Kano" or "His and Her Circumstances".
Nagisa (ace) is from Yume de Aetera
Mizuki (Supdon3) is from Comic Party
and finally, according to Kris at least, Bangusetsu means April Fool's Day!