If you are an online teacher interested in using grader readers with their learners or bricks-and-mortar teacher looking to promote extensive reading, I have recently self-published a digital graded reader. It is aimed at learners at the top end of pre-intermediate and the lower end of intermediate.
It is a fast-paced, contemporary and (hopefully) funny story about a detective who goes undercover as a trainee English teacher in Brighton, England. It also contains a range of innovative activities that exploit the connectivity of ebooks.
Check it out at: http://www.markjoliver.co.uk/brian-british.html