Geoff: The functionality you seek is available in circles.m, which is described here: http://www.mathworks.com/matlabcentral/fileexchange/45952-circle-plotter/content/circles_demo/html/circles_documentation.html
Slightly easier than
hc = circle(...);
set(hc, 'Property', value)
would be to change, in circle.m, the 'style' argument to 'varargin', and pass all those additional arguments straight to plot, ie.