I can tell you that it is possible to print to large format printers( plotters in other words) with mappoint. When you refer to making the area between the points bigger, you are talking about scaling. I don't believe MapPoint handles this. I think that the responsibility of scaling relies on your printer. The options of scaling can be set when you are printing. We use all HP Plotters where I work so you are out of luck if you use something else ;P

Something to think about. Plotters can print via HP/GL2 scripts and I know for a fact that you can set scaling in those. I am not sure of how that would work between mappoint and the Plotter though. I don't work with printing much just Geography ^_^