Welcome to our board,
Thisisnotelizabethbush! Do you remember (or have some idea) where (which publication) these sketches are published in? We have bits & pieces of various sketches of FMA characters by Arakawa-
sensei posted in our
FMA manga forum as they get published in various books (FMA Chronicle, Perfect Guidebook, FMA Rough Sketch Gallery, etc.)
like this, although I don't know which specific sketch you're looking for and hence I can't guide you to any specific thread...