BusinessWeek has an update on the art title insurance being offered by ARIS:
"Art title insurance through ARIS has been available for purchase since June, 2006, and it has underwritten more than 300 policies. ARIS clients include private collectors, dealers, art funds, and major museums and investment entities, and the values of the works insured have ranged from $20,000 to $4 million. (ARIS has been approached on a $100 million transaction that hasn't yet taken place.)"
There's a one-time premium ranging from 1.75% to 6.75% of the artwork's value, for "a life-of-ownership policy that can be passed on to heirs. ... In an ownership dispute, ARIS will cover legal defense expenses and the cost of the artwork if it is lost." Authenticity is not covered, however.
I had some thoughts on this about a year ago here.