As for suggestions.
Everyday I too think of new characters to edit, so suggestions are great although...
There are actually two very important criteria to create a decent looking character.
1. The character has to have a human(ly) face. (so predator, stewie griffin, aliens or something like it are pretty impossible)
2. The character can not have a beard. Its very sad but when you scan a face on PES, you cant scan the chin area AND it's not possible to add facial hair
So if the character you think of doesnt inflict with these criteria, it's pretty likely he/she/it can be made into a PES character.