Incorporate a OneNote demonstration mode with screen presentation tools like ZoomIt has (SysInternals)
ZoomIt does a great job at focusing and magnifying content during demos. The on-screen drawing is useful too.
Incorporate screen presentation tools like this in a OneNote "demonstration" mode. Control magnification to where the mouse is. Live or Still shot zoom. Allow the inking power of OneNote to be used to draw on the zoomed screen. Send zoomed and inked screens to OneNote for further use.