Here is how to submit a proposal to the XMPP Standards Foundation for consideration as an XMPP Extension Protocol:
Contact the XMPP Extensions Editor so that he knows to expect your submission.
Write your proposal following the guidelines described in XEP-0143: Guidelines for Authors of XMPP Extension Protocols.
Email the XML file (or a URL for the file) to the XMPP Extensions Editor with a subject line of 'ProtoXEP: [your title here]'.
Note: It is the author's responsibility to provide a properly-formatted source file (see the template and CVS repository). Proposals submitted in HTML, TXT, MS Word, Open Document Format, etc. will be returned to the proposal author for proper formatting.