I've only read reviews, but a few years back there was a study about Elagabalus that argued virtually all of the bad traits and excesses attributed to him were unsubstantiated. The book was The Crimes of Elagabalus by Martijn Icks.

Here's the best review I could find: http://www.timeshighereducation.co.uk/418066.article

If you're interested, it might be exactly your cup of tea, as Icks doesn't talk just about the historical Elagabalus, but goes through the entire history of how he has been portrayed in various ways through the ages and up to today.

Actually I think Caligula is quite unfairly demonized. Unfortunately, we have to rely on Suetonius, who thought he was mad, and Philo and Josephus, who as Jews were rather biased against him. Suetonius presents Caligula as a young man who suddenly gets absolute power and becomes a crazy tyrant. However, there's no reason to believe he went crazy with power, since he grew up watching his father, Germanicus, and other members of the royal family. So he should have had a fairly good idea how to behave as a ruler.

He spent a number of years with Tiberius on Capri, and this is probably where the problem lies. He watched Rome be governed from outside the city, so he never developed any skill at managing the senate. Augustus' rule, of course, had depended on maintaining a delicate dance with the senators. Augustus could not rule overtly as a tyrant, so he developed an intricate system that amounted to essentially stage managing the Senate to give him what he wanted. This made it palatable enough for the senators to work with him.

Our friend Caligula never learned how to perform this "delicate dance". Furthermore, he was probably worried about his own legitimacy. Augustus had ruled by military force, but he concealed his dictatorship by claiming to have the most auctoritas, or authority bestowed by achievements for Rome. Augustus had of course actually achieved quite a long, so the senators could swallow their pride and accept him as Princeps. Tiberius had been bestowed the powers of maius imperium and tribunal powers during Augustus' lifetime, which effectively made him heir without calling him one. Caligula succeeded Tiberius only because he was the next male heir, which revealed the monarchy quite openly.

Caligula therefore had reason to believe his rule was shaky. There's no reason to think he went mad with power. In fact, he was very popular at first, thanks to his father's enduring legacy, and he tried to bring his family back together after Sejanus' purges. He was certainly a jerk to his uncle Claudius and a bit weirdly infatuated with his sisters, though.

The crazy things Caligula is most known for is are things like prancing around calling himself a god, or making his horse a consul. It seems more likely that he just had a very sarcastic sense of humor (and admittedly a bit of a sadistic streak). When Caligula fell gravely ill, many brown-nosing senators offered themselves to the gods in his place. These were empty words of course, because the way to succeed in the senate was to please the emperor. Caligula, however, hated their servility, so when he got better, he made many of them keep their promise!

The charges of incest with his sister seem like stock insults. Cicero and Catullus made use of similar charges against people they hated, so it's unlikely that they should be taken too seriously. Suetonius claims that Caligula spent the entirety of Rome's treasury, even after Tiberius had hoarded it. However, Claudius could afford to pay a huge bribe to the army after his succession and doesn't seem to have been strapped for cash in the least.

As for declaring himself a god, it was probably just an insult to the Senate. Caligula and the Senate really couldn't communicate on any level. He would deliberately say crazy things because he knew they would just display cringing servility to him, so he kept making them do more and more idiotic gestures, like declaring him a god. The senators knew what he was doing, but they knew who held all the cards so they had to keep going.

This complete breakdown of communication is what led to the plots against Caligula and his ultimate assassination. Caligula knew the senatorial honors to him were all a fraud, and the senators knew he knew, and he knew they knew he knew... etc. It couldn't keep going on, so Caligula had to die.

Sources: Suetonius & OSU's Professor Nathan Rosenstein

The revisionist tradition with Domitian is fairly strong, particularly among archaeologists who have recognized at least as far back as Syme that virtually all of the balls credited to the Four Good Emperors were set rolling by Domitian. There is also a fairly strong tradition of Nero revisionism, perhaps most notably among art historians such as Eric Varner. They can point to evidence of Nero's popularity in the provinces and democratic tendencies. Caligula, as noted in another comment, also has something of a revisionist tradition, albeit much smaller. There are also what can be called counter revisionists, who attempt to critically examine the actions of supposedly good emperors. Trajan's destructive and needless warmongering, Augustus' brutality (although Augustus usually ends up alright), and Marcus Aurelius' disastrous early German campaigns can come under fire.

However, to a certain extent these debates are all somewhat in the background: anecdotally, I hear far more about individual emperors and their successes and failures from literary scholars than from historians. Most historians in my experience tend to follow Fergus Miller in downplaying the active role the emperor had. While particularly in the city of Rome the emperor could make a large difference and his actions could make an enormous impact on a personal scale, the empire as a whole tended to keep on chugging through thick and thin.