O.K., it's of course necessary to account for the source impedance when calculating the resistor values. I presume you know that it's essential for achieving a high current source output impedance. But it doesn't change circuit bandwidth.
A your previous bandwidth measurement was apparently affected by load capacitance (and possibly other parasitic circuit capacitances), we are still waiting for a correct measurement of the actual circuit bandwidth.
But apart from issues of measurement setup, there are limitations of feedback active current sources.