Whilst you are waiting for the fabled Vietnam issue, I'd like to point you in the direction of this great little Kickstarter:
Although Laotian-focussed it overlaps with Cthulhu by Arclight. Looking through the creatures some are similar to Vietnamese creatures, and some are brand new.
Well worth a look for inspiration, especially the ghost noodle seller looking for her killer.
It appears March is a month of surprise appearances, not only for Sixtystone pulling it's finger out and actually publishing something, Dennis Detwiller's near-legendary Dreamlands campaign "Sense of the Sleight of Hand Man" has appeared on Kickstarter seeking funds for completion.
The blurb: "The Sense of the Sleight of Hand Man is a complete classic Call of Cthulhu campaign set in 1920s New York and in H.P. Lovecraft's Dreamlands. It will be approximately 128 pages. It is a fully illustrated, mapped and lavishly
detailed tabletop RPG PDF book, written and illustrated by Dennis Detwiller (me). This work will be finished by summer 2012."
The Kickstarter page is here: http://www.kickstarter.com/projects/arcdream/the-sense-of-the-sleight-of-hand-man
Please go and show your appreciation even if you don't like Dreamlands because at the very least this campaign is the exception that proves the rule. I should know - I edited part one of the campaign that appeared in Worlds of Cthulhu.