https://www.bg-wiki.com/bg/Meeble_Burrows
Majority of drop location info is courtesy of Tachi on the Test Server Findings forum, I copied below info from the article(s) I put up on BG Wiki.
The following items are purchaseable with research marks after completing the associated rank of Meeble Burrows expeditions:
Adjunct Rank (20,000 Research Marks each): Cheruski Needle, Brigantia Pebble, Sljor Ring
Assistant Rank (20,000 Research Marks each): Charivari Earring, Beatific Earring, Dominie's Grip
Instructor Rank (25,000 Research Marks each): Sabong Earring, Fountain Ring, Fierabras's Mantle
Associate Researcher Rank (25,000 Research Marks each): Thall Mantle, Aswang Sash, Volos Strap
Researcher Rank (30,000 Research Marks each): Praan Coil, Panthalassa Sash, Lasaia Pendant
Researcher Emeritus Rank (50,000 Research Marks each): Leoht Gloves, Nemetona Cap, Veikr Pumps, Briscard Cuisses, Medala Cape
Known boss drops (maybe more, this is just what's been seen on test server so far):
Goldwing: Alcedo Gauntlets
Silagilith: Vara Brigandine
Surtr: Ankylosis Wand
Dreyruk: Alcedo Cuisses
Samursk: Devilish Scythe, and probably Adflictio (HQ/glowy version of Devilish Scythe)
Umagrhk: Abatteur Subligar, Orunmila's Torque
Use Julian's dat mine to look up the weapons and armor since they aren't on the real server yet so the stats aren't yet on Wiki:
http://www.juliandev.com/ffxi/TEST2012-09-07/
You'll see that in the dat mine there are plenty of new items that aren't in the lists above, so it's possible there's more stuff that just hasn't been found yet. Some of them can be obviously identified as crafted items (the ones with NQ and +1 versions), but there are a few rare/ex ones which have no obvious location, so they are most likely also from Meeble Burrows since there is no other content in the upcoming update.
Out of the equipment in the lists above, I'd say really only some of the researcher emeritus items and maybe one or two of the boss drops are potential side/upgrades to existing equipment. Most of the rest is pretty trashy or very marginally useful.