Dynamically add / duplicate custom meta in custom post types

I will answer myself after some research 🙂

while there might be appropriate ways of coding this with some custom function, for me there’s no need to reinvent the wheel when there’s a neat plugin that does the job

it’s called “advanced custom fields”

http://wordpress.org/extend/plugins/advanced-custom-fields/

it has a “repeater” to let admins add more fields dynamically

it also manages datepicks and fieldsets… basically everything I need!

hope this is helpful to others