If the Dosbox setup doesn't use a scaler, that means he'll be running 320x200 on a monitor designed for 1366x768 or higher. That's likely pretty unplayable especially for some. I've bad a couple of games do this to me on my laptop. Small picture, the rest is black.
I wasn't trying to pick on his wording, guess I just took what he said too literal, and yes, you're right, it would probably be pretty unplayable. Anyways, I was just asking for more information to see if I can help him out.
Sounds like he has the same problem you had, if that is the case, it might be good if you both send a description of the problem to support ( if you havn't already), so that they can add a support article on this problem for less experienced users.
t'was a long time ago since I last had a similar problem. Can't actually recall if I fixed it by a setting in BIOS or in the gfx card setting panel. I mainly put games into windowed mode though. For games still running in fullscreen I get full height and black borders to the side to avoid stretched graphics. But then again, I haven't downloaded any Dos based games since they introduced Mac support