Some things I’ve been kicking around:
- A Nietzschean reading of Islam: could Islam be read as an attempt to develop a form of prophetic monotheism that embraces master morality rather than slave morality? Particularly striking here is that none of the Qur’anic prophets are martyrs — the Qur’an even refuses to admit that Jesus really died on the cross, and it rejects Christian monastic asceticism as well. Further, could Shi’ism, with its attachment to lost causes and defeated martyrs, be read as a reintroduction of slave morality into Islam?
- Comparing Muhammad and Paul, starting from the similar ways both deploy Abraham as a way of maintaining both continuity and contrast with the pre-existing monotheistic tradition. I’ve written up some thoughts on this previously, and it seems like the topic I am closest to being equipped to write about “officially” (after reading some of the Islamic critiques of Paul mentioned in comments to that post, to be sure).
- The weirdly Altizerian character of Hodgson’s concluding reflections on the role of Islam in the modern world — he ends by saying that even if Islam should eventually cease to exist as a distinct institutional religion, then perhaps the Qur’anic challenge can still authentically live on in the secular world by means of literature. (Not much more to say on this one other than to point out the parallel.)
An und für sich 
Are you familiar with Peter Sloterdijk’s Nietzschean reading of religion? He doesn’t rely on the slave/master framework but rather uses the tightrope walker of Zarathustra to describe the athletic asceticism of religious practice
I am not familiar. Does it seem to you to be a more relevant model for Islam in specific?
Nietzsche’s master–slave dialectic isn’t, strictly speaking, necessary—and it may do more harm than good if you’re going to try and develop a hierarchy of Islamic sects based on the moral value of success or failure, which isn’t even the basis for the master–slave dialectic. But it is worth noting that Islam develops in a context in which the nascent movement triumphs over its local opposition, and simply doesn’t face the kind of foreign power problems that made Judean/Israelite states historically rare in Palestine and environs. Christianity develops out of/in parallel with diaspora Judaism, within and under the Roman Empire, and it learns to grasp for power from below while upholding that context.
Islam, on the other hand, kind of has the whole world to itself in the early Medieval period. Border conflicts around the edges of what becomes a reasonably internally diverse Muslim world, awareness of outsiders and their ways, but no such fundamental rootlessness as is caused by repeated tramplings and displacements. The kind of stable world that the Hasmoneans could only dream of. But in such a stable world, as it grows over time, there will be “losers” of conflicts that do not therefore disappear. They occupy spaces in adjacency to the more dominant groups. And they succeed in their own places, on their own terms.
So I wouldn’t call it an attempt to develop something different, though contrast with Judaism and Christianity obviously plays a role; I’d say it simply developed differently, even as it incorporated the same kinds of sectarian divisions internally.
Nietzsche does not espouse a “master-slave dialectic.”
I don’t think so. He’s attempting to formulate a general theory of the emergence of religious thought and practice. He picks up where Foucault left off with the genealogy of ethics and argues that the separation of individuals and groups from day-to-day social life leads to new new regimes of practice, or ascetic forms of training. These regimes of practice are oriented toward transcendent models of life. Only later does the rest of society get pulled along once these new forms have been translated and softened. In this way, he accounts for cultural change, as well.
Nietzsche’s tight rope walker is the model of the cultural acrobat who makes the impossible seem effortless. He is a model for others to aspire to. I do not know how this would be applied to Islam, though. I know Sloterdijk mentions Islam briefly, but I can’t recall the specifics.