Pursuant to my previous post about finishing carpentry, I dressed up some stair posts with some custom mouldings (all primed MDF).

Original post (top of stairs) 
Pre-fabricated pieces 
Wrap with 3/4″ MDF 
Slipped a box on top with a cover 

Finished post (top of stairs) 
Finished post (bottom of stairs)
I had to cut 3/4″ off of the railings so that the new post would fit. I used a reciprocating saw for this. I caulked everything and the customer will paint them.