Netflix makes use of a few components that are not part of the general SDK, but the majority of the channel is developed with the same SDK available to all other channels. We try to make things available to all, but that usually requires some extra work to make the component more general instead of handling a special case. The Netflix channel is developed by Roku and the code is proprietary.
The roGridScreen component that is the main navigation model for Netflix is available in the SDK for all channels to use. The "sliding" transitions are automatic in some cases (and automatic for all channels-- example "retrieving...") and in others the Netflix channel may put up a special loading screen. These transitions can also be included in any channel developed with the SDK, see roParagraph screen and roImageCanvas.
--Kevin