Google seems to be helpful with a '"no-tipping policy" hotel' search term. A quick stroll unearthed the Grand Hotel on Mackinac Island and the Boulders (A Wyndham Resort Hotel) in Scottsdale. Inn At Union Square claims to be the only San Francisco hotel with a no-tipping policy. Enbassy Suites La Jolla in San Diego and the Seaport Hotel in Boston claim a no-tipping policy as well.

There are many others. Perhaps it would be helpful if everyone made a point of calling the reservations desk of their favourite hotel chain to ask if they have any no-tipping properties? If you do, post the results here (perhaps on a separate 'No-tipping policies' thread).