TFS - Creating a Branch from Local Source

Well that was frustrating.

The Problem:
Work has been performed on the source Trunk that now needs to be in a separate branch, and not checked into the Trunk.

The Solution:
Create a branch selecting 'current workspace' as the source version
*Ba Bow* - nope, this doesn't do what you think it does, your shiny new branch does not have your local workspace changes.

Create a branch and merge the changes across
*Ba Bow* merges only work on checked in code.

Create a branch, shelve your changes, unshelve to the branch
*ding ding* we are on a winner, only it is a PITA to get it working.

Firstly you need the TFS power tools - here: http://visualstudiogallery.msdn.microsoft.com/c255a1e4-04ba-4f68-8f4e-cd473d6b971f
Next you need to, for some reason, ensure you have no other pending changes in your workspace.  I have no idea why, but even if you have pending changes competely unrelated to the shelve files, you will get warnings and may get errors.  Strange but true.
Next you need to call the "tfpt unshelve" power tool command. But you need to call this from a folder in the workspace you are working with as there is no way to set the workspace/server in the tfpt command.

tfpt unshelve MyShelfsetName /migrate "/source:$/MyPath/My Path with spaces/MyBranch" "/target:$/MyPath/My Path with spaces/MyOtherBranch"

Finally, when you run the command you will need to merge all the shelved files into the new branch, one by one.  You can perform an auto-merge, but this will actually perform a merge on the destination/shelf, when in reality you very likely want to take the shelf version rather than do a merge, which requires you to go through file by file.

The link below is a good source of information on this process.
http://codereferences.blogspot.com.au/2012/02/migrating-shelveset-from-one-branch-to.html