I have not connected my scope up to the power supply to check for ripple yet, but my multi-meter claims 1VAC is present at the input to the Buck (along with 34.8VDC). If that means what I think it means, then I've got about 3% ripple at that point.

Beyond the Buck, at the 5VDC and 3.3VDC points, no AC voltage is detected. Still gotta lug the scope out there and rig a stand for it so I can have a more graphical view of it all.