How do I make a long rope of fondant? I need to do a peppermint swirl rope border affect for a cake and I'm not sure how I'd get a nice long even width piece....

Other than carefully rolling it out by hand, you can used Edna's method for rolling out gumpaste or fondant for pearl borders seen here http://designmeacake.com/id71.html starting at timestamp 1:48 or use a clay extruder.

I just got a clay extruder for my birthday and it is fantastic!  I really loved playing with it.  It did the job so neatly and easily.  I think it was the Makin's professional extruder - my husband got it from Amazon.
 

I just did mine by hand the other day.  I did it with only fondant but I was making "straws" to go into cupcakes.  I rolled out red and white separately, then I left the red lay and I wound the white around the red.  Once it was in place I rolled my right hand away from me and my left hand towards me to get the twist together.  I just kept doing that small portions at a time.  Now I did mine to be pretty skinny and I cut mine along the way.  But you get the general idea.  Good luck!