Resplendent Chests only show up in special (randomized?) encounters within certain locations, I think there was one in the Cathedral during the beta. In my experience with them they drop some pretty good loot. What map locations can I look for these encounters and can I do it more than once?
THERE ARE NO SET PLACEMENTS FOR ANY RESPLENDENT CHESTS
Yes, they are generally at the end of a minidungeon, and yes, there are some along the maps generated in the game, but they are randomly placed, and are not always in the same area. Even in the minidungeons(if there is one, since sometimes there are none) they aren't in the same generated area of the map.
As for hunting for these chests for loot, it is not worth it anymore, as they decided to make Magic Find no longer affect the loot from chests, so better gear dropping is not as likely anymore.
If good armor is what you are looking for, you can find really nice gear for really cheap if you just get gear with 90% of the stats for 2k-20k, instead of the top stats for upwards of 1-25mil.
Actually, I'm fairly certain that in all dungeons, except for maybe cellars there is a small chance of finding one of these chests. I.e. I farmed the false crypts in Act 1 for a while to get the Matriarchs Bones event, and sometimes I found these chests, and sometimes in the same place there was only a normal chest.
They're basically the equivalent of Diablo II's glowing golden chests. They just have more gold + higher percentage of magic items in it. They can practically appear all over the place (of course with some restrictions), even in the overworld.
Act one, fields of misery;
In single player start from the quest beginning and run to where the Scoundrel is to save your checkpoint.
After that run left to find either the "Old man" tree boss, next to a resplendant, or the Dead beast that when you kill opens the cellar with the man and his ... "Wife"
If neither of those are there, restart your game, its like 3/5 games will have one or the other.
You have a very high chance of getting such a chest on the second level of all random dungeons with multiple levels. For instance in the Cathedral on the second level there isn't always such a chest.
They can also spawn on the edges of a map, mostly at places where you don't come around if you rush through the game, but they can occur also in all other places on the map.
Notice that all chests aren't affected by MF any more so it is more viable once you reach level 60 to farm the elite packs, cause they will always drop a yellow item.