An old friend of mine from Brooklyn, NY, Michelle Herman, professor of creative writing/comparative lit at Ohio State University posted using an emoticon as an ending paren.
As in her quip:
"OK, I hereby declare myself in charge of deciding how to punctuate using a parenthetical emoticon: said emoticon WILL do double-duty as a close-parenthesis. (And that is the last word on that subject :)"
Hmmmm... Whaddaya think? It is economical. (This is certainly a case for the Typophiles :-)