Per this guide in 2001, it specifically states in the 2nd paragraph of the Island One section that he sells the unstackable Jade Inlaid Coffins, but not the stackable ones.
http://www.angelfire.com/freak/eqjon...1/posguide.pdf
Per this guide in 2006, it still specifically states that the Key Master does not sell Tiny Jade Inlaid Coffins.
http://mysite.verizon.net/drexxell/eq/planeofsky.html