Deploying Pos .Net isn’t hard, but it’s not ideal either. You can see a thread I started on the subject on the Pos .Net forum here.
There is no merge module or redistributable exe/msi file for just the runtime components. In order to deploy Pos .Net you must run the SDK install, the same install that a developer runs. During the install you will be given the option for ‘Developer’, ‘User’ or ‘Custom’ installation, if you select ‘User’ then just the runtime files and configuration are installed.
If you want to deploy Pos .Net with your own application you need to run the self-extracting exe for the Pos .Net SDK, then embed the extracted files in your own setup program and add an instruction to your setup script to run the setup.exe for Pos .Net with a specific set of command line arguments. The Windows Embedded Team Blog has a post with the command line arguments here, note the arguments are case sensitive so be sure to use the right case in your setup script.
While this works well enough, it has the disadvantage that you must include the full sized SDK install in your setup instead of just the runtime files and dependencies. That will increase download times and bandwidth usage when deploying your application, and with no benefit to your users for the additional size.
Apparently there used to be a separate redist, but this was canned in favour of the ‘User’ option in the SDK install. Given this, it seems unlikely Microsoft will return to publishing a separate redist, unless perhaps there is significant lobbying from the developer community for one. If you’d prefer a separate redist, then I suggest you leave a comment on the Windows Embedded Team Blog post where they talk about deployment, or in the thread I started on deployment in the Pos .Net forum.