Hi Joseph,
I am not entirely sure what you are trying to accomplish, but I just posted about mixing non-breaking spaces (Shift + Space) with CMS content and maybe it will be helpful: link to post.
Also, there is another topic here that mentions the use of Ctrl + Enter to force a line break.
If that doesn’t answer your question, could you please give more details about what you are trying to do?
EDIT: After some playing around with plain text CMS fields, it looks like they strip all Shift + Space and Shift + Enter characters once you save, and Ctrl + Enter doesn’t work at all. So please disregard my above solution. According to this page using a Rich-Text field is the only known workaround at this time.