I could've sworn I used to have use a really good one of these call "Podio" or something, however after searching for several hours I haven't been able to find it.
It's only been ~6 months since I've used.

Anyways, I am looking for a browser based ftp client I can install alongside of a members-only website.
Preferably something with strong support for drag & drop and with a nice UI UX.
Also, If it's skinnable / moddable with html, css, js, php, sql, etc then that's even better

I have looked a few for my search results, but I was hoping somebody here has something they love and want to share.

man.. i must have been stoned the day i wrote this. that grammar.

I found it!
Pydio is the name.
4 days later..