Ilya Somin nicely clears up some confusions about what's commonly called the unitary executive. There are two issues: the scope of executive power and its distribution. The unitary executive view is that the president's authority over the executive (an intra-executive issue) is absolute. I would have thought this to be absolutely clear in the Constitution, but apparently some disagree. A separate issue is about the scope of executive power. How much authority does the executive has with respect to the other branches (an inter-branch issue)? In other words, unitary executive allows the president sovereign control over what happens within the executive branch, but this other view sees the executive power as expansive in a way that many find controversial. The problem is that many people keep calling the latter view by the term "unitary executive".
As Alito explains, one can consistently support a unitary executive with a narrow range of powers (which is roughly my position). One can also consistently support a unitary executive with very broad, almost unlimited powers (John Yoo's view, and also that of the Bush Administration). You could - also consistently - endorse a nonunitary executive with broad powers. The latter was the position of liberal Democrats during the New Deal and for many years afterwards, when they endorsed both broad executive power and the creation of numerous executive agencies outside presidential control.
Is there an example of someone who both denies the unitary executive and thinks the executive has a limited role? Given that both positions serve to limit the president, perhaps hardly anyone seeks to try both ways at doing so, but I'm curious whether someone has tried.