Unsolicited Recommendation

I need to write a letter offering a problem solving recommendation to an audience who is not expecting the letter. It should be a REAL problem (not made up) in business situations, and wirting a letter to the person in charge of the policy or practice that has caused the problem, persuading him or her to change it.
1.- demonstrate the seriousness of the problem
2.- having a real chance of effecting change
3.- counterargument
4.- emphasizing the positive.

the letter should be 1 or 1 1/2 page.