I know a place that does special financing. It's called owner financing. And you can structure the terms any way that you and the owner find mutually agreeable. If you know how to work a financial calculator, you can experiment with all sorts of scenarios. If you don't, then a Realtor probably does; an accountant certainly should know.
What you've described probably could be presented as something like an interest-only loan for 11 months, then a small balloon for the principle. You'd just have to present it in such a way as to make sense and be attractive to the seller. And that might mean that the effective interest rate would be equal to or greater than current mortgage rates. Or, to work it more to your advantage, make the effective interest rate equal to or slightly greater than the amount the seller would receive if he put it into a savings account.
Talk to an accountant or Realtor (one who knows and is comfortable with creative financing and owner financing) for more information
Hope that helps.