Well, if you were using Firefox and wanted to invest just a timy amount of time, a guy over at the TivoCommunity.com website created
a similar extension. TivoCommunity also runs on vBulletin 3, so it should be an easy conversion. (I'd also recommend asking permission to hack on his extension, to be polite.) There's also a second extension on that site that creates a search plugin for the bulletin board.