Amazon offers a White Glove publishing service. In this program, your agent works directly with Amazon to publish your book.
I wrote not too long ago about agent-assisted publishing, and this is just another incarnation of the same process. You might end up walking this road if the traditional publishers reject your agent’s efforts to place your book. But again, you end up with the agent as your book’s advocate.
On this road, you don’t travel alone. That in and of itself can be a boost to your passion. The fact that it can also boost your career sweetens the deal.