Any ideas for a co-ed baby shower cake? The shower theme is Raggedy Ann and Andy, but the colors are green, yellow, and brown. They're not finding out the sex of the baby...I'm a little lost.

I think you have your idea right there in the theme- Raggedy Ann and Andy! Not sure of your level of expertise, but you could do figurines sitting on top of the cake or a FBCT and incoporate those colors into the clothes or the rest of the cake, even the borders...Then you could write something as simple as welcome baby on the cake. Here are a couple of cakes for inspiration:
http://cakecentral.com/modules.php?
name=gallery&file=displayimage&pid=782753
http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=9116

Raggedy Ann and Andy are blue and red though. I just don't get how the girls came up with the theme-- this cake is for a friend, so I'm free to do what I wish with it.

Could you do raggedy Ann and Andy's faces/hair but use the shower theme colours in their clothing? I think if you still did the coveralls/ dress and apron, but in the browns and greens it would be instantly recognizable and would fit well with the theme. As well, if the shower is soon, those seem like fall colours, so you could do the dolls on a hay bale, or in a pile of fall leaves and get your colours that way.