Minor Description
Wicket's MultipartServletWebRequestImpl uses commons ServletFileUpload internally, but there is no way to configure this component, for example to propagate fileSizeMax inside.
As supposed in http://apache-wicket.1842946.n4.nabble.com/org-apache-wicket-util-upload-FileUploadBase-fileSizeMax-td4668001.html there should be implemented:
1) add Form#fileSizeMax and pass it to MultipartServletWebRequest
2) add MultipartServletWebRequestImpl#newFileUpload(FileItemFactory)