I have a potential scenario where we may have to limit certain pages of a site to members only access, say for a sports club with over 1000 members, it would be great to be able to "import" a list of members form a CSV file, likewise, on an regular basis be able to run this script to update (create or delete) members.

I know there is an issue here in terms of password creation, but if a random password could be created on "create member" (not "update member") and then output as a download - or ideally emailed to them directly like a "forgotten password" link would, then they could log in and change it themselves. The key thing would to not overwrite existing members passwords, only issue one one first creation for a member.