I did not have anything specific in mind pertaining to bank angle limits and as is commonly the case, Rick's thoughts are what I would have on the subject. But AC 25-7C is the gospel on transport certification, so download that whopper and search it. I do not think you can search it without downloading it your computer first. It's almost certainly a load-factor driven limit, but it's a bit more complicated when other factors such as gust envelopes, nav reception, and other things enter the picture.