Just today a friend and I were randomly generating worlds trying to find a woodland mansion close to spawn, and we found it! This is probably the closest woodland mansion to the spawn ever found for Minecraft 1.12!
I could go on about the seed, but why not watch the cinematic and find out more for yourself!
And the seed is!: "LoveMindcraft101"
(If you decide to make a movie or share the seed, it would be appreciated if you credited me for the find. You can search Youtube for "Stingray Productions" to find me.)