Would it be profitable? Perhaps, although this isn't about profit it is about a custom carbon fiber front lip for the 4 fog bumper I can assure you Supercowboy is not making money/profit off these lips. He wanted 1 and needed 9 other people to want 1 before they could be made.
Your assumption is correct that more people are running USDM front ends that JDM/MDM. You said you want a clean OEM look the JDM bumpers are OEM and in my opinion much "cleaner" then the USDM bumpers.
No one is penalizing you for having an USDM front bumper. As far as lip options I have seen plenty. Most are homemade or modified to fit... what do you except for a early 90's economy car that isn't a Honda?