There are indeed nonparametric alternatives. The nparLD R package and SAS macro (sse attachments).
You could also use the ARTool: http://depts.washington.edu/madlab/proj/art/ The authors claim it can be used with repeated measures, but I am not sure they are wright.
When data is non-normal that does not mean you have to resort to a crappy nonparametric procedure. The familiy of Generalized Linear (Multilevel) Models offers all you need for basically any type of response variable. Read more about it in my book (chapter 7):