Have a front buyer purchase the auto, then have a notrized agreement with them that you make the payments and after the last payment is made they give the auto to you.
Or get in good with the finance manager or owner of a dealership. They can do lots of things when they want to. They do this kind of stuff for friends and family all the time.
Use an attorney trust account. The dealer will just think you got some settlement and will accept a ACH transfer from a law firm.
There are lots of ways that can be done.