How is this feature of the CMS progressing? Would really need to sort things in a list manually.
Go to your collection template and add a 'number' field,
Then go to your collection items and order them as you wish.
eg. your first post is 1, last one is 6, etc...
Having, for example, 50 portfolio projects in a list you want to re-sort would be a lot of work with this method. Planning this ahead would be time consuming. This should be a drag and drop thing I feel.