thirteen23 (not 7eleven) is a design focus development company specializes in WPF application. On their website I found a few cool WPF application which not only looks nice but also showcase ability to connect to services on the cloud such as Windows Live Messenger.

Here are some samples which I think can be reused for your own enterprise app:

continuum: WPF based MSN Messenger

Foresight: A Vista gadget to help manage task + project

Mix08: a quick Vista application that lets you create your own conference schedule, keep track of times, and browse all the sessions.