I have a ton of custom built vampire furniture we never used in my Oblivion mod Unholy Darkness that I would like to port to Skyrim. What do I need to know and do to make this happen?

Currently no nif is directly ready to go into skyrim. You need to effectively swap out the model data with an existing game nif to ensure any collision and other misc data is there and functioning.

So does this mean some sort of nif surgery, or are there 3dsmax Skyrim compatible tools out there, or what exactly do I do? I have searched for info and I can find are tutorials for getting weapons and armor into the game, nothing on statics.

I worked with this tutorial by Insanity Sorrow (although written for weapons):
http://tesalliance.org/forums/index.php?/topic/4634-3d-craftworks-importing-weapons-into-skyrim/
to import my teddybears, my rockinghorses and my lightstaff into Skyrim (as well as a lot of other objects for my private use).
Just choose an existing object similar to that you want to import and follow the instructions.