my questions would probably be better suited to a frame builders forum but, any reason one could make a Ti seatpost for much cheaper with a normal piece of titanium tubing, like this
Titanium Tubing 1"OD x 0 038" Wall x 12" 99 94 Pure Grade 2 | eBay
and then either get a clamp, or since that would be ****ty, cut/drill it for a clamp like this
my only concern is with the grade of titanium, i did notice that the tubing you can buy specifically for a seat tube is actually the same wall diameter
however it's grade 9 (alloy) rather than grade 2 (pure)
Grade 9 contains 3.0% aluminium and 2.5% vanadium. This grade is a compromise between the ease of welding and manufacturing of the "pure" grades and the high strength of Grade 5. It is commonly used in aircraft tubing for hydraulics and in athletic equipment.
i cant tell if that means pure titanium is stronger (but harder to work with) or the opposite?