I recently gave the Twitter world a tease of Skype UWP running on my Lumia 1520 on Redstone (WHICH IS THE MINIMUM REQUIREMENT. If you're on 10586 or Release Preview.. It's not going to work) and promised to share with the world. Without further ado, I present..... PACKAGES.
I'll be updating this regularly with links to the official Skype UWP packages that support W10M.
Before downloading the appxbundle, go to Settings -> Update & Security -> For developers and enable Developer mode (may work with Sideload apps, but I never tried). Copy the package to the phone and open it from the File Explorer. Install then enjoy. You can also upload the package from the Device Portal also, if you feel well inclined to.
NOTE: You MUST be running a Redstone build. If you try this on a non-Redstone build and you complain that it doesn't work, I'm going to steal your soul.
If you are installing via File Explorer, wait for it to complete even though it looks like nothing happened. Using the Device Portal is easier because you see the entire progress of the upload and install.
Skype v. 11.6.56
Skype v. 11.6.36
Skype v. 11.6.26