The human eye can only distinguish 7 colors easily. Therefore, as you said, it does not make any sense to assign a color to each owner. Do you have to display everything on one sheet? If not you could attach a list with parcel numbers and corresponding owners, meaning that you can label your parcels with the numbers, instead of long names. Or what about using colors to classify owners according to their second name (e.g. names from A-F = blue). It depends on how people will use the map. But if they simply want know where person X has a parcel then that would be a quicker way to find these parcels.
Or you could also include multiple data frames, with each one zooming in at a different spot. I prepared a quick thing for you. Not very artistic nor accurate (the individual frames�?? content do not match the main frame), but it should get the point across: the map in the middle will show your entire area, and the boxes around it are the zoomed in areas (which �??pop out�?�). You would have to figure out how to squeeze in legends still but that could as well be accomplished with enlarging the paper size (what will people be looking at? A JPEG stored on a computer or perhaps a poster? The latter would make it easier, for example). If you are allowed to have multiple sheets you would not even need to have multiple dataframes. You could simply make multiple maps (and you would have plenty of space for legends) and finally make a general map which indicates which map depicts which area.
Thinking about it now�?� look at my second attachment. Made this map a while ago and it might help to further explain what I am talking about.
