Don't you guys worry, we have found a way to install mods (almost) from what I can find. All the credit goes to Byteandahalf. Here's a video by him showing the very first mod for Minecraft Windows 10 Edition :
Note that he uses DLL injector for this, but I am sure this will definitely change in the future to an application dedicated for Windows 10 (something similar to BlockLauncher).
Also, here's a video of him explaining how vTables work for Minecraft:
Hope this helps each and every one of you!