I would agree that hand drawn caricatures are art and possibly more so that an exact replica of the person.

Fair enough, but do you think that it is enough to alter an original photo or painting a little bit and then call it your own?
Much art is just applying an existing image to canvas or paper. Portraits of living people such as the Mona Lisa or landscapes such as the Hay Wain were just the artist copying what was in front of his eyes.

The only problem I see with selling caricatures is that it's often seen as comic street art which is high on entertainment but low on cash value.