Oh yes, I have asked this a couple of times and never really got a response.  The biggest problem lies in that the editor has to exist between the form tags.  So adding a form in the editor closes the form early thereby preventing submission.  I have a major need for this functionality and the only way I think I can compensate is through the use of tokens.  The form would be built and stored elswhere and would be replaced when the text is rendered outside of the editor.  So something like <<LOGIN FORM>> would be replaced with the actual form.  I think I might be able to use the Code Snippet box to provide the tokens.  However, it would be great at some point if we can just drop a form in the editor.