  Two-field slow-roll inflation is the most conservative modification of a
single-field model. The main motivations to study it are its entropic mode and
non-Gaussianity. Several years ago, for a two-field model with additive
separable potentials, Vernizzi and Wands invented an analytic method to
estimate its non-Gaussianities. Later on, Choi et al. applied this method to
the model with multiplicative separable potentials. In this note, we design a
larger class of models whose non-Gaussianity can be estimated by the same
method. Under some simplistic assumptions, roughly these models are unlikely
able to generate a large non-Gaussianity. We look over some specific models of
this class by scanning the full parameter space, but still no large
non-Gaussianity appears in the slow-roll region. These models and scanning
techniques would be useful for future model hunt if observational evidence
shows up for two-field inflation.
