As for in rem jurisdiction, that doesn't apply at all to patents since the locus of patents is the entirety of the US. From what I recall from so many years ago, it doesn't apply well to personal property like a painting either as the locus is easily changed. It applies, if at all anymore, mostly to real property.
I'd wager that the res of the vast majority of United States Citizens resides within the District of Columbia, and that their res being there is what confers in rem jurisdiction for actions levied against property within the several States, including the basis for the ability of the IRS to seize personal property, which could include a person's patent, if appropriate circumstances exist. Within a patent itself, if the patentee did not make a showing of possession or control of a res, I don't think they have basis to make assertions relating to that res, in rem.
