Could offer us the option of displaying X # of characters for these long OU strings (and perhaps any others), wrap them in a span, and set the span's title to the complete string? I would guess that most often, the first characters would be the most important to distinguish each of the OUs - probably don't need the full OU path when viewing - and can always save as Excel/CSV to get it all, say for printing.
<td><span title="full OU string">First 20 chars of OU string...</span></td>