Ive just been browsing the web and discovered your message.
My name is Michael Bona and i was born in Pendine West Wales and christened in Carmarthen.
My dad (Michael Bona Snr) has told me that the family moved to Wales from Italy possibly in the late 1500's, i think there is evidence of this at St Davids church in Carmarthen as there is a record of a Bona being Christened there.
He believed they may have been cobblers by trade, not sure if this is any use to you but may help.