Oversize western horse bridles.?

My horse takes an oversize english bridle and my trainer and I don't think a full size western one will fit him because we tried one. I was wondering if anyone knew of a place to get an oversize western bridle that is good quality I do NOT want something cheap. If you know of any places online and it has to have the option of bridle sizes. Or a place in colorado that has oversize bridles.