Ok you guys inspired me to send the following email to the friend who is organizing (thank you so much, yortma, for the wording!). You're right - at this rate, it will cost me well over $100 and I'm not prepared to spend that for someone that I'm not even friends with. We'll see what she says:
My goodness, Jen is popular! I never imagined so many guests at a baby shower.
As a hobby baker, I'm not equipped to make a cake so large. My...