Artists' Choice
I think a fun theme would be Artists' Choice in which each site artist gets to draw a companion, accessory, and/or background of their choice.I believe when artists get to take a break and have more freedom to do their own thing, some great pieces can come out of it.
The whole thing would be like a giant surprise and perhaps the artists can surprise each other by what they come up with. It's more or less like a grab bag.
Anyone else interested to see this happen? =)