I don't know of an addon specific for this purpose, but I do know that Gatherer used to keep track of old-school random spawn chests throughout the world, maybe it keeps track of these now? You will need some sort of source file of course, I believe there is one available with data from WoWhead, just search for it. =)
I don't feel an addon is really needed for this, as you would basically just be looking at a map. Such a map can be found in the following WoWhead guide for Timeless Isle:
http://www.wowhead.com/guide=1902#ac...ure-everywhere
Happy hunting =)