Create a custom line with a user-specified particular slope to reflect a custom user-defined capacity model (custom version of the red line)

I regularly use the classic agile gadget on dashboards to evaluate the overall progress of large projects. We typically avoid story points and instead look at solely at remaining hours (hours tab). So we're looking at the classic agile gadget for a 12-18 month period. When I look at the red line, it's automatically set to start with the amount of work remaining in hours on the start date set in the gadget's configuration and then is rendered in a straight line where 0 is at the end date as set in the configuration.

This is nice for uses where the number of hours on the start date is equivalent to the capacity of your team given some velocity (I run a model for long projects that assumes N developers at M%utilization thereby giving me a capacity in terms of how much available scope measured in time that the team can handle at any date in the project); however, in reality our backlogs are never quite built so perfectly, so what I'd like to do is have the ability to add another line to the burndown gadget that represents the capacity of the team. This would be in addition to the current red line.

I would want to specify the following information:

1. Start date
2. Capacity on start date measured in hours
3. End date
4. Remaining amount of work left on end date. It would probably be ok to set this to 0 and I could probably make do with not being able to configure this value.

Then the software would render a line based on that information. This would allow me to see how I've modeled effort and then as I'm monitoring the team's progress, the goal would be to make sure my green line stays near this model line. It would also make it very clear if I had room in my model to add scope or if I had to start thinking about cutting scope.

Additionally it'd be nice to allow hiding of the currently implemented red line.

One additional problem that the current implementation of the red line in the gadget imposes is that you search for a date in time where the amount of work in the backlog approximates the team's capacity that you are trying to model and you are then not able to see anything prior to this.

I know this may not be how folks intended the tool to be used in terms of long projects with burndown charts spanning many months, but the tool does a great job for this type of project except for the issue mentioned here.

I'm running jira 6.0.8 and have been unable to find anything in the docs for future versions that suggest this is possible.