This is sort of a Bokeh filter, right?
Actually, Bokeh is just the result of blurring image parts with high brightness contrast using the right kind of filter kernel (f.i. disc or hex, gaussian wont work->too soft).
HDR DoF is the usual application. Building larger kernels isn´t such a prob with the hex filter since it has linear complexity. Adding additional passes with the right sampling offsets can give you quite a large radius.
But I´m not sure in how far this works well for the disk kernel.
A common technique is to render sprites to achieve the bokeh effect where it is necessary. This way you can have quite large, arbitrarily formed results. wink