Is there a report which shows which students are working below, at expected, or exceeding levels in internal assessments?

Go to;  Reporting> Assessment > Steps > On Track Reports

You can select from a range of On Track reports e.g. simple or extended, or Special Cohorts. 

Select from the drop down the choices you need for example academic year, year group/form and click Choose. You will be given the percentage of students in that year group who are working at the different levels. This will also provide a summary of students in a table below. Example of how this will show is below: 

You can find out which students are working at each level in each subject by clicking on the percentage figure.