Kioti does offer bigger buckets with the quick attach system. They just don't offer the 66". They have a 60" 72" QA Bucket, 84" QA Bucket (for the DK65) and they are coming out with a 78" QA Bucket for the KL1595 Loader. The 60", 72" and 78" buckets are all a Univeral Attach, so they will fit on any of the QA Plates. But obivously you wouldn't want to use a 72" bucket on a KL1450, that would be an over kill and would be overloaded to easly. So its not a matter of strength just a matter of what size QA buckets they offer. Personally i would like to see them come out with a 66" QA Bucket. But if you really wanted to im sure you could get another bucket with the same "univeral attach" in a 66" size or around that size, as it will accept any "bobcat" style QA style attachement.