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: 
Figured I'd leave this answer in case someone sees it now.
It seems like they've cleaned this up since it was asked, and that old wiki doesn't link well to the current website:

<https://www.orfeo-toolbox.org/download/>

There are full installation instructions as well here <https://www.orfeo-toolbox.org/CookBook/Installation.html> where they have downloadable install scripts to run.

If you are using ubuntu, you can also do

```
sudo apt install aptitude
sudo aptitude install add-apt-repository
sudo apt-add-repository ppa:ubuntugis/ubuntugis-unstable
sudo aptitude install otb-bin otb-bin-qt python-otb

```

This was the thing that worked for me after 30 minutes of trying a full build from source.
I tried installing Orfeo Toolbox in QGIS on Mac and struggled a lot but eventually managed it. Here's how for any beginners confused by terminology:

<https://www.orfeo-toolbox.org/download/> (download MacOS)

Make sure the file does not end in .txt, if it does, remove this so it just ends in .run (On recent Mac OS, you need to Right click and "Get Info" for the file and delete the .txt in the "Name & Extension" box, not just rename it in Finder).

Go to terminal, navigate to your Downloads folder by entering

```
cd Downloads

```

Then run these commands:

```
chmod +x OTB-7.3.0-Darwin64.run

./OTB-7.3.0-Darwin64.run

```

(Making sure that the file path is correct). This will unpack the file.

Then go to QGIS > Preferences > Processing. Click on the Providers drop down menu, and select OTB.

Input the file path name of the otb application folder (will probably be something like `/lib/otb/applications`)

Then input the file path name of the main OTB folder.

Tick the activate box.

Press OK and you're done!