As Günter mentioned you can build a snapshot from all you Dart source including packages. To create a snapshot:
$ dart --snapshot test.snapshot test.dart
This will create the snapshot file test.snapshot. You can run your snapshot like this:
$ dart test.snapshot
The snapshot test.snapshot is self-contained, and only need the Dart VM to run, which leaves you with just the two files dart (dart.exe on Windows) and test.snapshot to deploy. Also the snapshot is platform independent, so the generated snapshot can be used on both Linux, Mac OS and Windows.