Extend Issues Type and Priority behaviour

Right now, issue types and priorities are merely a lable, a description and an icon. I would like to see something much more useful.

Part of this is because I expect to modify the workflows to encapsulate our business processes to the greatest extent possible by JIRA and what I can con our "Powers That Be" into letting me do.

I would like to be able to assign different work flows to different types of issues.

For instance, our feature requests have to be prioritized by a specific committee (at least major feature requests) so the workflow for feature requests will need to go through a workflow that takes it through that committee processes where it will be prioritized and scheduled and so on before being sent to development.

In addition each issue type needs to have a diferent set of information. A good example of this is with the current setup. I think that for the most part the environment is not meaningful for new features. If I'm going to have different workflows for each issue type, I'm going to need different data to run those workflows.

I would also like to have different priority sets for each type of issue.

I think it would also be useful to establish who can create which types of issue (as a member of the public, I should never be able to create a task, for instance) and also which priorities they are able to set. It possible that I only want certain people to set the priority to certain values (for instance the "Oh no! Fix this now or the whole company is going into the toilet" priority should probably only be set by Managers).