Ejector rods! Brownells had both Cressent head and Bullseye Ejector rods in stock as well as steel ejector rod housings. You can also get stainless housings if you like that two-tone look.
I havr the bullseye on one custom 41 magnum and plan to add it to all my vaqueros in the future. As well as my blackhawks iuts just works. A second option is the ejector assembly from a 357 maximum (which is longer than the standard one) for more complete ejection of fired cases.
You can also fit either the steel grip frame from a Vaquero of the longer one from a superblackhawk to a regular blackhawk. Another nice mod is to user a superblackhawk hammer on a blackhawk(when not using bisley parts) It would look good on a birdshead framed gun I think.