If you're using the command line as was suggested in your other question, you won't be able to achieve what you want. The real issue is getting files from change sets associated with a work item means you have no configuration context. You'll need a workspace or stream to give context to where the files reside. You could use the plain Java API to retrieve the content but you would still need a workspace to resolve the file paths.

You could use a workspace for all this work like the RTC builds do. When you deploy, you would want your workspace updated with the change sets from the work items. You can use the workspace to resolve file paths and extract the files you want to deploy. Of course, you may run into issues with gaps when accepting from work items instead of working from an integration stream.