When working in Modeling Mode, one can bake vertex data to the model. Options include AO, Curvature, and the Vertex Normal.
Unfortunately, it seems the Normal-output is only available by itself under RGBA. One can pick either RGBA or per-channel when baking vertex data, and the normal output is seemingly tied to RGBA.
Under per-channel, you only get 2 options, which seems a bit of a waste with two other channels that could be filled:
SUGGESTION: under per-channel, allow the X, Y and Z channels of the available normals to be selected. In this manner one could have AO, Curvature, X/Y normals across RGBA and compute the Z-channel of the normal in the shader. Alternatively, one could pack a 3channel normal with AO/Curvature?
Such options will allow a client to fully-utilize all available vertex channels with useful data.