I could copy all images for the product and create new rows in the
product_images table (the one used by attachment_fu) but this seems a
bit inelegant, does anybody know a 'better' way or if attachment_fu
supports this functionality in some way ?
Nope, it doesn't support that. But if it did, it'd probably create
new rows in your attachment table and copy over the attachments to the
new copied records.