Nowadays we see lots of local app stores for iOS and Android all over the world, at least there is 2 legal app stores else than Google Play in my country.
Is it possible to create a custom store like that for windows phone?
There are custom ROMs for some WP devices (googleable); also, if you developer unlock the phone officially, you can install apps (up to 10) via datacable.
But there's no quick "allow 3rd party" setting like on Android, so running a store for casual users is unrealistic.