How important is bow length in relation to draw length? I am looking to buy a bow, preferring the value of a used one. I have a 26-27" draw length, and the charts I've found suggest a 58" recurve (Great Northern's site. What issues would there be if, for instance, I found a 60" or 62" recurve, or a longer than suggested longbow, considering my short draw length?
It varies depending on the shooter. Some people seem to be able to comfortably shoot shorter bows than others. Draw length is a major part of this, but not all of it. I don't shoot longbows at all, but I have trouble shooting bows shorter than 60" in recurves, and I have a 28-28 1/2" draw. I struggle with some 60" bows, and I don't shoot any 60" bow as well as I shoot 62-64" bows. Most charts will recommend a 60" bow for my draw. With your draw, a 58" will not be a problem, but you will probably find that a 60-62" draws smoother and is more stable. I think there is a point where the bow gets too long to be comfortable; 64" is as long as I like in a recurve. You really need to shoot some different length bows and see what feels right for you, but all things being equal, shorter is handier for hunting and longer is smoother, more stable, and better if you are shooting targets.
When I did the research for a hybrid LB I was told by more than one bowyer to use, 2x draw length+4-6", to realize the full potential of the bow.In your case that would be about 58-60". However the bow I chose was62" and I find that the bow does well for me. Take Pauls advise and try different bows and lengths to see what does you good. Try some friends or local shoots or go to a show.
In a recurve, there is an optimized draw length to bow design to get the maximum speed out of the bow. This does not mean that a longer bow won't shoot well for you or fast. It just means the bow is not operating at maximum efficiency.
I shoot 68 inch longbows for one reason. At my draw length they don't stack at the end of the draw cycle. Throw in that longer bows are more forgiving of shooting form errors and longer bows are a win / win in my book.