Interesting idea. Demeteorizer will help you create a bundle that can be installed anywhere. You would then be able to use this on a desktop computer.
There are a few things you need to keep in mind when using node-webkit
1) You need to load the URL that is running the server, which is what gives your the resulting Meteor application. This is not strictly the same as node-webkit.
What you can do is use the html files in /static to do this, since they can be used with node-webkit. You can then have your meteor server somewhere else. The app would load on the desktop environment instantly. Though the DDP portion of it would connect to the remote server to store/retrieve data.
(There was an app called popcorn-movies which used a similar technique. They had their server (not meteor) somewhere and used the static files to connect to it).
2) If you consider running the server locally instead of remotely, you would need a MongoDB locally. Additionally you would need to run the app (which would be seperate from node-webkit). You could also modify the bundle meteor gives out