You may try All American Coating in Tampa.
Ceramic Coating | Tampa Bay, FL | All American Powder Coating
or PerformancKote in Orlando.
Performance Kote - High Performance Automotive Ceramic Coatings
They both offer a black satin ceramic coat.
I've seen some the PerformanceKote's work on other peoples equipment, pretty nice looking.
I don't know how the durability of Black Chrome is or what effect it would have on your mufflers since the entire side pipe would dipped for the electroplating.