This might be silly coming from a noob like me, but........(please don't laugh
![Oops! :oops: :oops:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
)
If you want to do it hollow just to save weight, could you not just use a bandsaw to cut four sheets (one from each side) off of posts similar to those rustic looking ones used in the table you've shown, leaving you with a solid centre core. You could then cut a reasonable slice from the end grain and use it at either ends as a filler piece. If you mitre all of the joints, perhaps it would all go back together to look something like it did before, but it would essentially be hollow?
Not sure if ths helps or if it would work practically, but I thought I'd suggest.....just in case :-k