Well, it used to be (in Eve's era) that to get smethign made out of Zesuaium, one had to go to AvaNet, the society of godlike artificial beings that once inhabited Yamatai's southern islands (It was called Geshrintall at the time). Yui eventually forced them to leave while she was Empress), and Ketsurui Zaibatsu and its associated corporate family (WickedArms, Ketsurui Fleet Yards, etc.) took over as the sole producers of Zesuaium.
KZ tends to be much more mass-production oriented than AvaNet was. With AvaNet, one could ask them for anything from a sword to a statue made of Zesuaium; With KFY, their production power is almost totally directed at military manufacturing like starship hulls. Getting a Zesuaium skeleton would be extremely difficult and expensive, unless you could find a "pre-owned" one somewhere (PNUgen Pagoda no Uesu would probably be the best place to look).