extra arduino shield with buck regulator

Greetings,
Has anyone tried to use an additional shield to step down the 13.8V needed for the peaberry to, say, 7.2 with a buck regulator?
I was thinking to make another layer:
bottom - middle - top
arduino uno - shield with LM 2576, inductor, & caps - iambino on top.
then I can wire the middle layer to the 13.8V, route the output 7.2V to the "Vin" of the arduino, & don't have to have a separate wall wort for the uno/iambino.
Does this make sense & what do you think?
Has anyone tried to use an additional shield to step down the 13.8V needed for the peaberry to, say, 7.2 with a buck regulator?
I was thinking to make another layer:
bottom - middle - top
arduino uno - shield with LM 2576, inductor, & caps - iambino on top.
then I can wire the middle layer to the 13.8V, route the output 7.2V to the "Vin" of the arduino, & don't have to have a separate wall wort for the uno/iambino.
Does this make sense & what do you think?