The multiple millions the 121212 Hurricane Sandy relief benefit concert at Madison Square Garden raised for the Robin Hood Fund continues to swell, thanks to musicians that autographed instruments and equipment used during the historic event. CharityBuzz.com is collecting online bids for a number of one-of-a-kind items, including autographed guitars, clothing worn by some of the participating musicians and other items.  Leading the way (as of 12/14) in the auction that ends Thursday (12/20) at 5pm (Eastern) were a Fender Bass autographed by Paul McCartney, Bruce Springsteen, Roger Daltrey, Billy Joel, Eric Clapton, Jon Bon Jovi, Dave Grohl, Michael Stipe and others that had a top bid of $38,600. A Fender guitar signed by McCartney, Springsteen, Joel, Clapton, Grohl, Stipe and  Eddie Vedder was just $100 behind the bass and a very close third was a Les Paul with the names of most of the above. Several other autographed guitars were being valued by bidders in the $7,500 - $10,000 range.  Other items doing well included the shirt Bruce Springsteen wore during his set ($9,500), a saxophone signed by former president Bill Clinton ($12,000) and a meet & greet with Jon Stewart and 4 tickets to his Daily Show stood at $4,000 - a grand over its estimated value.  The most over estimated value placed on a item in our estimation (and apparently that of bidders, too) was the $10,000 assigned to the personal backstage pass worn by Chris Martin of Cold Play and signed by him and Michaedl Stipe, which had received only 4 bids and was stalled at $1,600.