In an effort to make this meet the rules of 'The Workplace', I'm looking for generalized advice and will only be providing a high level overview of what's going (which also happens to help with keeping things a little private). If it's still off topic, I apologize in advance!
Background
In the spring of 2015, I began to take on multiple responsibilities that aren't in my job description - because I really enjoy them. My Director said she would work on getting my title/role changed at some point down the road. Fast forward to today: My boss quit, and the Director is leaving in January. As a result, all knowledge of my unique role in the department will be lost (aside from co-workers, but I'm concerned about the 'higher ups'). I asked the director if she would be willing to write a internal reference for me of sorts, to explain to whoever takes her position what my role has become and the efforts being taken to get my title/role changed. She agreed, but asked that I draft the letter, so that she can review and tweak it before signing it.
The Question
While I asked for an 'internal reference letter' - I have no idea what that should look like. It appears the internet doesn't either - all I can find are discussions about letters for promotions, reference letters when applying to a new company, etc. I had a hard enough time getting the hang of cover letters, this is completely uncharted territory and I'm hoping someone may be able to provide guidance. What I have gathered is that a letter for this situation should contain and be laid out as follows:
[Who is the person we are talking about?]
[What was this person doing when they were first hired?]
[What *specific* examples illustrate that their responsibilities changed?]
[Why are these examples useful to the department/company?]
[What actions are being taken that should be continued, in regards to a role/title change?]
The biggest issue I'm running into is that the last part ends the letter off kind of awkwardly:
Therefore, I have been working to make Joe McGuy VP of Everything. Sincerely, Director
On top of that, now that I'm going over everything - I'm wondering if this is even a good idea? Are some of these pieces not okay at all? Is saying I should be promoted a complete faux paus, even though the director told me I would be and then asked me to write this letter? Since it seems there's no good template of an 'internal reference letter', is it okay to just provide what I have written to the director and let her prune it? If this letter is ok to write: how long is too long? (I'm placing my bets on anything longer than 1 page).
Thank you in advance - and again, I apologize if this is off topic. Seems to land squarely between the "maintain employment" (good) and "asking for advice on what to do" (bad) categories.