I think I'm pretty good at creating content, just hoping there was an easier route.
Obviously I don't know your talents and abilities. There is a HUGE difference between "I think I am pretty good at creating content" ...and actually "creating good compelling content". Then writing a sales letter or a multi-sequence marketing campaign that compels people to TAKE ACTION.
How many copywriting programs, books, have you gone through? Have you hired a pro to mentor you? If not then you will most likely fail. Not trying to be overly harsh just stating the reality of marketing/copywriting. There is way more to it than common sense.
The other fact is your looking for a custom mailer that works ...for free.
Be very careful with this...
Anybody that has actually spent tens or hundreds of thousands of dollars in writing and testing a good DM piece will never hand it over for free.
If you do get something for free I would be very suspect that its actually worth mailing.