Taken from Peter's site (bio section):

In early 2005 Peter starred in Retirement along with George Segal and Rip Torn. At this time the 70th Columbo MOW is currently in development.

Any ideas on what MOW stands for?

MOW=Movie of the Week.

Sorry, but I wouldn't read too much into that blurb. Peter has a long history of talking-up future "Columbo" projects that were not (yet) really in the works at the time. It's a way to keep the ball rolling.

The phrase "in development" doesn't have a specific meaning. When something is "in production", it's time to get excited.

Thanks Ted. I would have thought if a new movie had been made then we'd have known about it by now. We can only hope!