When we need an admin panel for a client to use to be able to update their own website [ie - they're not CuteFTP trainable

] we usually build the site into a WordPress backend - that way they can just log in and update there. It still means they need to know a bit of HTML or at least understand enough to copy/paste existing code, but it's been a good solution for those clients who wish to try their hand at updating a bit sans FTP.
I'm not sure if that helps you really, since you mentioned you looked at WP already.
Otherwise, I honestly don't have a good suggestion but would love to know if someone else has something in mind!