I have been using the Perfect 10 black hair dye and I'm seriously considering going to a rich dark brown. I don't want medium or light brown hair. I just want it to be a little softer but I still want to be dark without being black. Can anyone suggest a hair color that would get the results I'm looking for?

You should go to a salon for this, changing your hair colour so dramatically (more than 2-3 shades) should be done professionally. Also you can show them exactly which colour you want, and they will dye it that colour.