This might be kinda low-ball but one of the most important classes I took in highschool that got me where I am today is Advanced MS Office workshop. Where we learned how to setup userforms in vba for use in excel.
Being good at Excel and being a "Spreadsheet nerd" firmly placed me in my current position as a financial analyst.
Things like setting up meetings in Outlook and all that jazz are marketable skills in a wide variety of positions.
Finance: Excel, MS Outlook
Marketing: Photoshop, publisher, ms office, excel (aggregate mailing list manipulating)(Teach differences between 5color process and 4c digital print colors, show pixelation of 4c digital prints vs 5c ink etc. - color calibrated lights, editing marketing copy and making revisions and stuff in PDF's)
Design: 3D Cad, catia, rendering software etc.
Project Management: MS Project, excel, ms outlook
Also look into teaching basic setup in MS Lync - every office I've been in uses this program for communication and screen sharing and internal webinars etc.
For marketing/business content design, have kids build a portfolio of nice logos and graphics and datasheets/brochures that they can take to an interview. Digital prints (4c) are okay for portfolio pieces. Have them learn different weights of paper and cardstocks etc. *Gloss vs Matte* etc.