The Interface Builder integration is fantastic now. You really should be using it, it's worth the time it might take to port your CIBs to XIBs. Lots of things just work for Cappuccino in IB, including bindings and custom table cells.
Syntax highlighting in Xcode isn't working so well with Xcode 4. TextMate and Sublime Text 2 are the more popular environment for Cappuccino editing right now, I think, while using Xcode only to edit the UI files.
Cocoa was given its name because, at the time, it was intended to be built on Java. Cappuccino is a play on Cocoa. So while it may not be directly built on Java, its name did descend from Java.
Sofa built a great app, enstore that lives on under it's new owner. Plex also has a Cappuccino component. Pixar built an internal app a while back. There are various others we've mentioned in the past, and several internal apps which unfortunately the public will never see