I do have some of those done (Cerberus, Nadeshiko Kinomoto) I still need a good manga image of Masaki, but I haven't seen any, as well as Sonomi Daidouji, Takashi Yamazaki. I've been using colored illustrations so far.
There is a small snippet of guidelines in the Cardcaptor Sakura Wiki: Guidelines page but I think it is a default that gets created when the wiki it's self is made. I meant to make a rules/how-to for images as there are some users who upload large batches of screen captures. It should be up in a few minutes.