Refillable Leather Journal

Looking for a leather journal that supports A5 refillable inserts that will last as long as I do, ideally something extremely high quality that will patina overtime. Budget is no concern, in fact the more expensive and high quality the better(it is a special gift). This thing will be used daily and ideally for decades to come.

Also any recommendations for paper inserts that are fountain pen friendly and can handle wet M or B nibs without bleed through would be great to know as well.

Thanks in advance.