After looking at Tim Hussey's photographs of Jill Hooper's studio with all of its handsome, well-worn art supplies, I started daydreaming about antique and vintage tools that could be used today, either as originally intended or in an entirely new way.
Paintboxes came to mind first. Old Reeves paintboxes ranging from vintage metal examples to one of the company's distinguished 18th-century boxes with original watercolors given by General George Washington to Nelly Custis* may turn up at Christies or on eBay. The detail images at the top show an eBay find, and pictured third is Turner's 19th-century box from the Tate archives. On its site, Winsor & Newton has other examples along with paint history.
*Christies auction highlight reported in Maine Antique Digest, March 2004.