The state of Art right now is that Glenn Beck has assembled and put up for auction, a piece of his own consisting of an Obama bobblehead doll in a jar of urine, reminiscent of the "Piss Christ" from way back when. He posted this on E-Bay with an asking price of $25,000 and had bids over $11,000 when E-Bay pulled the offering. Proceeds were to go to Beck's charity, Mercury One.
It seems that E-Bay does not allow the sale of bodily fluids on its site.
This brings up another possibility: Reminiscent of the portrait of the Virgin Mary done in elephant dung, how about a 3-D sculpture of the pres done in male bovine scat? This not only meets the E-Bay standards, but could probably be the best representation of the pres to date, on multiple levels.
With the artist's provenience that all the BS used in the sculpture was genuine BS from genuine bulls (not steers) I'd set the asking price at $50,000, proceeds to be donated to some worthy charity, say the Tea Party.
A common plaster bust of the prez dipped in ordinary liquid cow pies might be priced much more reasonably for the common man.