> I think this block of code should be a function

You mean a function in `mne.viz`? Alternatively we could modify `plot_evoked_topomap` to accept a list of times as the `time` parameter (and an `ncol` parameter).

> good defaults for vmin and vmax

The `plot_evoked_topomap` default is to use the data range, is a hardcoded default preferable?