I think a person could produce a red bird without black in the tail. I have a rhode island red female that has almost no black in her tail. I have been working on improving the red color in the female line for my barred rhode island and she appeared in some of the chicks. I am not sure what clears the black from the tail but what ever combination of genes that do clear the tail-black are found in buff breeds. It may be the combination of the dark brown , mahogany gene, columbian gene and wheaten gene. I know my RIR have the columbian gene and the mahogany gene they may have the dark brown gene.
Tim