Hi Mike!
First of all, I am happy to hear the problem is resolved. However, I would decorate the \XLite\View\Product\Details\Customer\AttributeValu es class instead of \XLite\View\Product\AttributeValues
The reason, why you could not achieve the needed result by removing template is because that template was not assigned into any view list. You can see it if you check the xc_view_lists table in the database.
Instead, the viewer class was assigned to the 'product.details.page.info' view list and this class is \XLite\View\Product\Details\Customer\AttributeValu es as you can see in the Webmaster Kit:
http://awesomescreenshot.com/0bf38f7ged
So, the proper way to work around it is to decorate the class as you did, but you also can remove it from view list as well:
\XLite\Core\Layout::getInstance()->removeClassFromLists('\XLite\View\Product\Details \Customer\AttributeValues');
Please, let me know if it helps.
Tony.