HN user
What do you think about this one? http://odoo.com/start/cms
It's not a standaline jquery lib but can easily be extracted from the code of Odoo as it's open source.
We worked a ot on the usability to make it smooth to handle images, backgrounds, specific properties of building blocks (e.g. banners, parallax, ...)
We built the same features in open source for the Odoo website builder. You can try it here: https://www.odoo.com/page/website-builder
We also put features like resizeable bootstrap column with drag & drop (col-md-X), link manager, media manager, special fields edition (e.g. prices with currencies)... Playing with building blocks look more sleek in Odoo version.
Github: https://github.com/odoo/odoo
Disclaimer: I am the founder of Odoo. We should probably extract this bit of code from Odoo to release a standalone library.
Odoo Invoicing has the features you need and his fully open source. https://www.odoo.com/page/billing
It implements: SSL, PDF, Export, same preview than print but no local storage. In the other hand, it has: online payments, auto generation (subscriptions), send by email or regular mail, etc.
One-click demo: https://demo.odoo.com/?module=account
(disclaimer: I am the author of Odoo)