Well, it's typical that just when you don't need it anymore (as I switched to a totally different discipline) the required functionality pops-up. I found that Vol. 13 (2011) of the Mathematica journal contains an article about these types of designs, [Computing Mixed-Design (Split-Plot) ANOVA][1]. I thought it good to post it here, as I know many people would love to have this. [1]: http://www.mathematica-journal.com/2011/10/computing-mixed-design-split-plot-anova/