I've never searched for a black french cuff shirt but I never imagined it'd be too hard to find. I definitely wouldn't start at the mall though. Try a Mens Warehouse or K&G type place. Both of those stores are in the Chicago area, I have no idea if they're national chains or not but they're of the warehouse shopping variety. They usually have everything I'm looking for.
K&G Mens Store
Men's Warehouse
EDIT - I just looked at both sites and couldn't find french cuff. I gave a pretty weak ass effort tho