We printed films with just the black on a 4800 for pretty much the reason you are taking about. In the end we never used the color part again, we ended up not doing Abby color prints on that printer anymore and just the 17" roll of film in it. When we got the 4900 I switched that to all black right away. In hind sight I wish I would of switched the 4800 to all black also, it just prints much quicker.
But by all means it will print films with just the one channel.