Are there any Historians before E. Said that studied the criticism of orientalism?

Said was interested primarily in literary representations of the Orient, and he was closely engaged with processes of representation and hegemony. Although these aren't necessarily the same thing, he used the same word—Orientalism—to refer to both, which is part of what makes the book both confusing and fruitful. Alas, he thought he was making a major departure from previous approaches, so these do indeed get short shrift in his work.

I think that Marshall Hodgson, in his Venture of Islam (1974), gives an even better—albeit not as well known or influential—diagnosis of and response to the problems in scholarship that Said would later note in a broader survey of literature. As part of a critique on preceding scholarship, Hodgson argued that the Islamic world should be examined not as a thing in itself but rather as a product of human agency, and as such, even continuities need explanation. This clearly deviates from some of the stereotypes that Said tried to uncover, and it's also a sound historical theory, so a few quotes might help out:

However a civilization be defined, it must not be hypostatized, as if it had a life independent of its human carriers. … The determinacy of tradition is limited, in the long run, by the requirement that it be continuingly relevant in current circumstances. (vol. I, p. 34)

Accordingly, it is wise to posit as a basic principle, and any deviation from which must bear the burden of proof, that every generation makes its own decisions. A generation is not bound by the attitudes of its ancestors, as such, though it must reckon with their consequences and may indeed find itself severely limited by those consequences in the range of choices among which it can decide. ... Historical change is continuous and all traditions are open and in motion, by the very necessity of the fact that they are always in internal imbalance. Minds are always probing the edges of what is currently possible. But even apart from this, we are primarily human beings with our personal interests to pursue, and only secondarily participants in this or that tradition. (vol. I, p. 37)

The misimpression that ‘the East’ has latterly been awaking from a ‘millennial torpor’ is still remarkably widespread. It results, of course (like the term ‘East’ itself), from the profound ignorance of world history not only among modern Westerners but among others as well, whose eager vaunting of the antiquity of their institutions was taken at face value by Westerners. (vol. I, p. 38)

I'd also like to mention Steven Runciman's History of the Crusades (1951–1954). Although he doesn't study Orientalism as such, his work is an implicit rejection of us-and-them approaches essentializing the Islamic world, suggesting that he similarly saw and tried to address problems that Said would find anew a generation later. It's also written in breathtaking prose that could be a worthy model for any historian today.

Marshall G. S. Hodgson, The Venture of Islam: Conscience and History in a World Civilization, 3 vol. (Chicago: University of Chicago Press, 1974).

Steven Runciman, A History of the Crusades (Cambridge: Cambridge University Press, 1951-1954).