Brennan's (2001) table 3.2 (synthetic data set number 4) contains item scores from a person * (rater : task) generalizability (G) study. Note that the data are in long format (one item score per row) and the facets are factors.
Arguments
Brennan.3.2
data frame in long format with a column for item scores and columns for sources of variance
Source
Brennan, R. L. (2001). Generalizability theory. New York: Springer.