Wanted: A courageous Portland artist with a big idea. The owner of an Old Port building will help raise up to $80,000 to replace a long-loved trompe l’oeil mural that is being lost to a $2 million renovation of the building at 80 Exchange St. The developer, a real estate and hospitality management company that owns and operates The Press Hotel up the street, is requesting proposals to replace the mural and has pegged the budget at between $40,000 and $80,000.