I did use Cameron's  Proof of funds letter that helped give me some credibility for foreclosure deals. 

While living/working in the house I will be working on it/upgrading it to gain equity and hopefully the house will appreciate (in the Portland OR metro area it should).In order to find the perfect house with seller-financing available, I'm studying hard so that I can pretty much mimic what investors do with these kind of properties by sending out mailers/yellow letters to get a bunch of calls/responses and find the perfect location in the Portland metro area.

Hello George.We all as investors face the same opportunities, finding a good deal and getting it under contract for what the property is worth (taking into account financials, terms, rehab, etc.) and getting it closed, so we can turn a profit.I can only assume you are just getting started in investing based on your question (I could be wrong), so my first action item for you would be to market to these owners through post cards, letters, door knocking, email, phone, social media, etc. so you can gauge interest in selling. 

I've read the majority of the articles about wholesaling and what the letters should contain, but I was just looking for a more specific approach.

Because, lets face it; most people are not making 100 plus offers a week, mailing out thousands of letters, driving targeted areas for dollars, or crawling through ditches, climbing fences or shaking palm trees to find these deals.

Does anyone have a sample pre-foreclosure letter template that they use to send to homeowners, to start discussion on possibly selling their homes?

I have been reading a book and an email letter that has talked about making sacrifices things to get something like real estate property.  

We paid the heir $50 or $100 to sign off on this letter we had our attorney review after we drafted it.  

We verify by student (or faculty) ID Card, or if they're incoming by an acceptance letter.

I don't think a letter giving 30 days notice will be enough for a savvy renter.