I think the effective profile also has to include the SEDs of all the separable profiles too, right?  (the h1 in "... int(h1 f3) ..." in the comments above).

We could multiply these into the bandpass I suppose, but that feels inelegant.  A chromaticized delta-fn SBProfile would work. (I effectively use these a few places in test_chromatic.py by creating chromaticized Gaussians with fwhm=1.e-8, there being no other way at the moment to draw ChromaticAtmosphere effective PSFs for a given SED/bandpass combination.)