I've never heard of such hybrid things, or of agents dealing in self-pub. Is that a growing thing?
I think it will be.
In my case, this is what happened: My agent shopped my first book around, and got squat from the big 5. However, he did get an offer from Audible. We held off on that for a while, because these days the big 5
will not sign a deal without audio (I found that out more recently with Singularity Trap, actually). Anyway, eventually we gave up on getting a print publisher, signed with audible, and put the book up on my agent's Agent Supported Publishing.
http://ethanellenberg.com/agent-sponsored-publishing/
I remember at the time, Ethan saying to me that if we can sell a few thousand units, we could consider it a success, and meanwhile we'd work on the next book. Then
Legion took off on Audible, everyone was very surprised, and Audible ponied up a contract for books 2 & 3.
The surprise was
how much of a difference it made to the royalty bottom line. I guess if you sat down and did the math, it shouldn't have been, but I get the impression no one had done that. Not only are my per-unit royalties significantly better, but Amazon and Audible pay quickly and without holdbacks. See
http://ethanellenberg.com/all-about-royalties/ for some info on that.
At this point, Ethan is starting to talk (informally) with his other clients about alternative business plans. Especially if you already have name recognition, going hybrid can be a profitable option.
I think what may happen if this catches on more, is that trad publishers will shift to a more service-oriented model and less of a distributer model. And there are things that publishers take care of that we are having to do ourselves (and by 'ourselves' I mean mostly Ethan). For instance, I just put out a signed, limited-edition hardcover version of the Bobiverse trilogy. That did
not go smoothly. Still having issues, really, with sales outside North America. Foreign rights have to be negotiated individually, movie options have to be negotiated (and take forever. Geological processes are faster). OTOH, you're in much better control of things.
I guess, like most things, it's all trade-offs, and you're limited by the options actually within your grasp. We've discussed putting one or more of my future books through a big 5 just to get the exposure, with the understanding that it would probably be a huge financial hit.