Linguafolio standards are a good place to start for objectives and for deciding what should be represented in the portfolios.
Linguafolio materials:
Linguafolio self-assessment grid (.pdf)
Linguafolio interpretive listening checklist (.doc)
Linguafolio interpretive reading checklist (.doc)
Linguafolio interpersonal communication (.doc)
Linguafolio presentational writing checklist (.doc)
Linguafolio presentational speaking checklist (.doc)
North Carolina is piloting an online portfolio at elinguafolio.org, but teachers/students can also create their own portfolios using Google Sites templates.
The Linguafolio World Languages Washington site includes downloadable LinguaFolio materials from Kansas, Nebraska, Virginia, West Virginia, North Carolina, and Wisconsin.