Hello!
As this is my first contribution I hope you'll be gentle
I've been using this spot for a while now, possibly 3-4 hours of actual farming.
So far I've made roughly 1.2 million credits, but it is hugely luck-related.
Friend of mine farmed it for a day and got one drop, I farmed it for less than a day and got five..
The place is a heroic phase on Coruscant and all the elites (and the one champion) have a small chance of dropping either custom belts or bracers.
As these are extremely rare, especially for non-light armor (since you can get a custom light armor belt for fleet comms), their value is quite above what you'd expect from a lv15 orange item!
I've confirmed three different bracer drops and also got two of the same belt, and on my server these sell for 200k per bracer and 250-300k per belt.
Seen some on GTN for 1mil but only an idiot would buy them for that price when you can farm them this easily.
All the mobs are lv16-ish and very, very easily dispatched with a level 40 Trooper, even faster with a level 50 shadow.
http://www.torhead.com/mission/53jRgwS/enemies-of-the-republic
You get the quest from Ensign Belkan in The Works and you can repeat it once every 2min after you break the first repeat limit.
Basically, you can get a drop on your first kill or your twentieth - if you are feeling lucky, this is definitely something you should try!
The best part is that it can indeed be easily farmed at 40, quite probably it's relatively simple even at 30.. Making it a perfect way to grind up for the level 40 or 50 mount and skill if you don't yet have one.
TL;DR:
Go in, kill ALL mobs, rinse and repeat. Luck is required, but as it takes about 2min per run I can almost guarantee you a 200k cred drop within the hour.. At my server prices.
:edit:
Current total is at roughly 5.7mil credits with maybe 12-13h of actual farming. Been quite lucky, but my buddy has made about 2.2mil so far and he's done it for about 10h, so even unlucky guys do get massive credits