Brainstorming for Digital Portfolio/ Multi-genre project:
Talk with students individually at the beginning of the semester to determine what their driving interests are.  This needs to be done early and before they know that I am looking to establish a topic so that their choices are not affected by outside forces.
Have students begin a KWL chart, writing about what they know about their topic, what they want to know, and at the conclusion of the project, what they have learned.
Have students develop a relationship with a mentor who knows something about their topic.  This mentor will have access to the student's writing
Make up guidelines for what the mentor will be expected to do so that participants will know what they are getting in to.  In some cases, I think that this might be a great inter-disciplinary assignment.  Perhaps if students do not have any definite ideas about what their topic may be, ask them what their favorite course is.  Go from there.  I really think that ideally mentors will be chosen from outside the school setting, but in some cases, I think that in school mentors may work (Gary Carroll, Dr. Goodrum, teachers who are truly experts in their fields).

Here are some links I need to keep up with:
http://www.readwritethink.org/classroom-resources/lesson-plans/creating-online-community-through-30671.html   This is a lesson plan.  It provides excellent instructions for setting up a blog and a great rubric for online portfolios.

http://www.users.muohio.edu/romanots/Tom_Romano.html  Here is the guru.  Check here for multi-genre project examples and rubrics.

http://www.mshogue.com/ce9/multi_genre/multigenre.htm  Lots of information from a school that performs multi-genre projects.