Oh, oh, oh! I do this! I do this in Prince of Yen! 
See, originally POY was supposed to be about Prince Derek and the princess he was wooing, etc. Janin just got thrown in for a different spice. But once he was in he wouldn't leave, he eventually stole the part of MC and even got the book names after him. 

But, he never got a POV. He has one or two POV scenes, but he is not the POV character. This gives me a unique perspective, while also feeling like I'm still kind of in control of my story... and, like you, Janin has secrets. 

So anyway, the first part of the book is from the third person perspective of Derek, who is not a minor character by any means. The first book is his story, his wooing of Katherine, etc. But it's set up for the second book... 
Book Two is written from the first person POV of Janin's brother Yancy. Yancy is passive, and almost completely absent from the story. Most of it he didn't even witness first hand and is retelling from what he was told. It makes it very interesting when he is there; because most of the time he's just a narrator and you forget about him and then sometimes you remember that that the narrator is also in the story. 
So yeah, I had a lot of fun coming up with that. I think it works quite well.