I agree that unless your fingers are much shorter than normal, most of the issue is practice, flexibility and muscle memory. When I started playing years ago, I almost went back to the store and asked if I could get a guitar with wider spaced strings as my fingers were 'too fat' to play the strings clean in an open c chord. Over time I found that my fingers were faster, thinner and longer than they seemed at first. The frustration is tough though. I didn't think it was possible to break into a sweat playing open chords at a slow pace, but I managed to do it. The mental game in improving an instrument is key--for me, especially at first, breaking my practice time into small chunks was helpful. Four 15 minute practice sessions with a few minutes inbetween seemed much more productive than an hour straight practicing. :)

JM