Fireplace ~

 

I would definitely indulge in a larger fireplace.  This will bring more warmth to the room, both figuratively and literally.   Maintain the rustic and ranchy fireplace look with something very similar to what you already have.  Some of the newer rustic looking ones have the funnel extending to the ceiling.  These are usually stainless steel and would bring in another reflective space, plus break up the dark framing around Josh’s paintings.  The stainless steel funnel also helps heat the room more (you said the room is very cold).  If building a chimney is not an option then just purchase a larger wood fire like the one you already have.  I would definitely not build a fireplace with a traditional white mantel piece.  To be frank, it will stick out like a sore thumb!  Remember you are wanting cosy and down to earth not elegant and sophisticated, plus the white would be too stark against all the dark wood.  If you favour the idea of a mantel piece, go for something more vintage looking.