Thanks Elfen.
I did some more research last night:
There is Super / Color and Power Mandelzoom by Robert Munafo (e.g. http://mrob.com/pub/muency/supermandelzoom.html)
And Adam Smith's Floating Fractals 5.1 (e.g. http://archives.math.utk.edu/software/mac/fractals/FloatingFractals/)
I did some more research last night:
There is Super / Color and Power Mandelzoom by Robert Munafo (e.g. http://mrob.com/pub/muency/supermandelzoom.html)
And Adam Smith's Floating Fractals 5.1 (e.g. http://archives.math.utk.edu/software/mac/fractals/FloatingFractals/)