Question: I already tried this <http://hg.orfeo-toolbox.org/OTB-Qgis-plugins/> repository and couldn't get it...

This guy seems to have it: <http://www.elance.com/samples/orfeo-toolbox-qgis/24111664/>

Answer: 
This is how I installed it on Windows 8.1 running QGIS 2.18.16:

* Download zip file for Windows 64bit version from <https://www.orfeo-toolbox.org/download/>
* Unzipped it to a sensible location (i.e. not a temporary location)
* Start QGIS
* Go to menu option Processing > Options
* Expand Providers > Orfeo Toolbox
* For OTB application folder set the value to be the folder path to the bin folder, for example if you have unzipped the download to c:\scratch then the bin folder would be C:\Scratch\OTB-6.4.0-Win64\bin
* Set the OTB command line tools folder to the same bin folder
* Press OK
* If you get a Wrong value error message about a msys folder you then need to go to Providers > Grass Commands and clear the value in Msys folder, this is some sort of bug in QGIS.
* Restart QGIS

**IMPORTANT: Folder path must not have spaces, so c:\Program Files will not work!**

*This approach got it working but I have not fully tested all the functionality. The reason is that I was interested in a specific function that it had.*
Here are some resources that answer your question:

<http://wiki.orfeo-toolbox.org/index.php/Quantum_GIS_plugins>

<http://osgeo-org.1803224.n2.nabble.com/Is-there-a-way-of-installing-the-qgis-plugin-for-ORFEO-Toolbox-OTB-td5963420.html>