Custom date fields

A feature I would like to see added, is to add custom (date) fields to a person’s record. I.e. for keeping record of wedding dates, date of baptism, etc. Our church keeps record of 5 different date fields in their administration (one being the membership date, which is already included in the current version and not including date of birth).

P.S. I looked through the other suggestions, I think a lot of them were already built / included in the current version, would it be possible to somehow mark those, like putting [done] in their post title?