Story point burn down by state transition - Sprint Cumulative Flow Diagram

Following from issues GHS-4136 and GHS-4139, I would like to request a variant of the same thing, which hopefully won't be rejected as well :-)
We would also like to support the burndown of story points but without either linking to real time or editing the story point field. A solution that would be suitable for us, and hopefully sufficiently flexible for others, would be to define partial burndown percentages for the intermediate columns. E.g. one could define an intermediate state/column "development complete - in testing" and associate the column with 70% burndown (with "complete" in the final column for the usual 100%). This wouldn't be 100% correct but at least more accurate and reflect some progress. If one could define the burndown % for any intermediate column in such a way in the board configuration then users could define as many partial burndown states as they wish for the granularity they seek. Clearly the result is that the burndown chart (and respective reports) would apply the respective partial burndown of the issues' SP as they progress through the different intermediate states.