How can I create fields for a project which are readonly for Reporters ?
The way I see is to make it a private field and assign the right to read private fields to the reporter role. But in that case every reporter needs a user account license. http://confluence.jetbrains.com/display/YTHB/YouTrack+InCloud
Who are Reporters?
"Administrator can narrow the permissions set, but cannot extend it. Once an account get any permission above the Reporter's set, it automatically becomes a user account, and is count against the license."
Example: The Fix Version of a issue should only be set by a developer, but the reporter should see this field in the issue as readonly.