Those are definitely good references as well. I don't know if you're aware of this, but the Founders' Constitution can be perused in an indexed online version. One page on that site that might be of interest is Marshall's opinion in Gibbons vs Ogden. About a quarter of the way down, he says, "But it has been urged with great earnestness, that, although the power of Congress to regulate commerce with foreign nations, and among the several States, be co-extensive with the subject itself, and have no other limits than are prescribed in the constitution, yet the States may severally exercise the same power, within their respective jurisdictions." Just another example of how the word was used that should give a good idea of how it was understood to mean.
Anyway, you still might want to take the OED for a spin when you have the leisure. You'll see what I'm saying about it.