There are others spud, but I can't think of the names off the top of my head.
Some are simple PHP drop ins and others require some extra coding work. I'm sure as android and ios apps develop more they will be easier to format forums for smart phones. I found a couple "model building" forums on that Forum Runner, and saw that it supported PHP, and saw this forum was built on PHP, and thought it might be a cool little plug in or something.
I stopped doing development/code writing a few years back, but have started tinkering with Android OS apps so... maybe I'll have a go at some of these forum apps. I'm sure there is a quick way to process the forum externally so there is nothing to add on the forum's back-end.
If I find anything I'll share it here!