I don't have a wide belt but do use Uneeda for custom belts for my Kundig Uniq edge sander.? Before my first purchase the Uneeda sales rep (Tom Espisito) provided suggestions of paper types based on my needs and had a few belts fabricated and sent to me to try out for free.? I have been quite happy with the performance and life (have never broken one of their belts) so I have stuck with them ever since.
Steve