@prasath.t did something similar to what you are wanting in this post which includes a downloadable example:
Perhaps you can adapt his work to your usage case.
Another, perhaps simpler option would be to overlay a standard chart over the bar chart and set the Background Color and Plot Background color to transparent. You would also probably want to set Show Legend and Show Popup properties to false.
Doing a quick experiment for proof of concept purposes, I was able to eliminate the rest of the chart's axis features by applying the following script to the configureChart extension function:
#def configureChart(self, chart):
domainAxis = chart.plot.domainAxis
rangeAxis = chart.plot.rangeAxis
domainAxis.setTickLabelsVisible(False)
domainAxis.setAxisLineVisible(False)
domainAxis.setTickMarksVisible(False)
domainAxis.label = ''
rangeAxis.setTickLabelsVisible(False)
rangeAxis.setAxisLineVisible(False)
rangeAxis.setTickMarksVisible(False)
rangeAxis.label = ''
This was the result:
