I have submitted a proposal to the Unicode Technical Committee with the following title.
A proposal for encoding twelve localizable sentence markup bubble characters, together with a request for action to set up an encoding infrastructure for the encoding in a separate standardization document of complete localizable sentence markup bubbles using those twelve characters
The document is available from a link labelled L2/13-079 on the following web page.
The meeting of the Unicode Technical Committee is due to take place from 6 May 2013 through to 10 May 2013 at San José in California.
A person can send in comments on the proposal and request if he or she so chooses. I think that comments will be listed in the Current UTC Document Register 2013 page and be available for public viewing. The first page linked below lists an email address to which one may send an email with a pdf as an attachment to the email. The second page linked below includes a form and is for typed text only.
William Overington
1 May 2013