Anyone coming to this page, please note that you really do need to kill the DARK ELF versions of the storage worker and shady treasure sorter. I spent about 4 hours last night killing the other ones (halfling or something) and the emblems never dropped. Reading all of the other posting history, it seems clear that only the Dark Elf versions of these mobs will drop the emblems.
Going back today to try this new strategy, will post with results.