MaNGOS, ARCEMU are the two that come to mind. I was really young and it took me so long to figure out how to use svn to get the code and then to compile it, so i always used repacks. Some guy on MMOWNED helped teach me all this stuff, he still makes private server content today.

The one I used was fully hosted by a third party. I don’t remember much in terms of tweaks except some client configuration changes, I think I had an account on some webapp or it just let me login with whatever.