Do sign languages have "accents" like verbal languages? If so, what would be some examples of those?
If we define 'accent' to mean a distinctive manner of expressing language characteristic of a particular group(s) then I would say that the answer to your question is yes. All that would be required for such a notion to be possible is a group of people stressing certain modes of their language in certain idiosyncratic ways.
This much has been shown to actually exist within sign language communities. Linguists researching the Philadelphia area have observed that a single meaning is represented by different mannerisms in Philadelphia compared to the rest of the United States. It is believed that the cause of this deviance is due to many deaf students in Philadelphia attending 'mainstream' schools, where the deaf students were less likely to be in the company of other deaf students.
This raises an interesting, overarching observation that most differences between accents in sign language communities occur between those who are deaf and those who are not. It has been suggested that deaf sign language users can determine whether another sign language user is deaf or not.
It will be interesting to see more research come out on this point.