I know that everyone's prices vary widely, but I'm needing some help with pricing this cake. I just received an email from a lady who found these two cakes on the internet and wants to know if I can combine them into one birthday cake. She wants the zebra one on bottom and with cream cheese frosting and the other in different colors and with regular buttercream.

First of all, does fondant cover cream cheese frosting okay? I've never done that.

Second, I'm just hoping to get some general idea of what a fair price would be. Her words were that she wants it 'big enough to look good' even if that's more cake than she needs because 'everyone can take some home with them'. She said 40-50 servings.

Thanks!

Yes, fondant will cover cream cheese frosting just fine!
This is how I price my cakes number of servings x$2.00= price. You may or may not want to charge more for the fondant work, I don't.
Here's a cake I did with the frosting/fondant mix you are talking about
http://www.cakecentral.com/cake-photo_1076523.html

jibbies

How much is it going to cost you to do the cake? The ingredients for the cake? The Cream Cheese icing? The fondant?