DNN is the most flexible solution with over 10K plug-ins, the framework allows you to get a site up and running in a few min, install a skin and apply it to both the site and admin control panel, or install 2 skins one for your control panel and one for your site, or install 10 skins and use a new skin on 10 different pages, the choice is yours. You can build and create 100's of containers (the look and feel of your modules, blocks, content area's, or whatever you want to call it)
You can style content modules directly - how is that a limit?
Collaborate your developers HTML with a copy of your installed skin and just rename it instead of page.ascx name it whatever.ascx and merge them, use the DNN tokens to facilitate login controls, or just merge their HTML in - simple, I do it daily.
Use paypal or whatever you want to authorize payments.
Email -Blasts and notification? there are a ton of options here (http://store.dotnetnuke.com)
All scheduler based, I used to send out emails from 40 different web sites within 1 install of DNN.
Videos? (http://store.dotnetnuke.com) I use Ultra Video Galley, super impressed, I feel like a star using it.
DotNetNuke is a crazy platform, and I can't think of another platform that has the flex this does.
- Sounds like the only limitation is your partner.
All of my personal sites use DNN and so do my clients.
I hope this helps
DWilson
ListenLiveMedia.com