Apache Guacamole is a clientless remote desktop gateway. It supports standard protocols like VNC, RDP, and SSH.We call it clientless because no plugins or client software are required.Thanks to HTML5, once Guacamole is installed on a server, all you need to access your desktops is a web browser.

Source: Apache Guacamole (incubating)

You set up your own server, then deploy clients on your desktops. Don’t know how well it streams video though…