I have an idea for a short (19") pedestal table that I would like to make with three feet mortised into a triangular shaped vertical. ... if there is a Best Way to do this so that I can have a length of wood in the shape of an equilateral triangle? Thanks!
What's the size of the triangle? Either the length of a side or half the "height" (distance from center perpendicular to an outside edge).
I'm assuming this is at least 8/4 stock, probably 10/4, maybe even 12/4. If so, my guess is making the final cut with the "waste" side being the piece you want (the above-described track saw method, or even on the tablesaw) is probably out just due to material waste/obtainability, not to mention cutting capacity with the track saw. You're not going to make a pedestal with a single piece of 4/4 stock.
The "raise the working surface of the tablesaw" method is pretty good, but you're still referencing a point against a fence and doing that accurately can be difficult. Then again, I suspect you'll probably round over the points of the equilateral triangle anyway for both looks and not cutting into people's feet when at the table. So, if you make the first cut, then round/chamfer the "point" of the two cut edges, you can reference that larger surface against the rip fence more easily and accurately. Then do the same treatment on the remaining two edges.
Another method is to use a taper sled with wooden/disposable hold downs or double-stick tape. You won't actually cut a taper, but the sled carries the work through the blade and the sled itself registers against the rip fence or miter slot. For a 30" high table this shouldn't be too hard, although the sled will take away some blade height cutting capacity, so you may want to use something thin as the carrier.
That said, you could use the taper sled as a taper sled as well, and have a triangular cross-section that decreases uniformly as it rises from the floor. This would involve saving off-cuts to hold the stock properly for the second cut, and the math is somewhat tricky, but do-able.