Hi Jim! This is actually precisely what we do. In fact all we do is secret passageways! We ship them around the globe. I'd be happy to share some information with you about the market.

There are both more simple ones (our prices start at 2.5k and more complex ones - we've done houses with up to 10 secret passageways over 100k). Many people are using a secret mirror which can easily be installed in place of a closet door. This is actually the most affordable model.

People love this because it transforms what was once a mundane closet space into a elegant entry way and safe place to store jewelry, watches and fur.

On the subject, about 25% clients use a secret passageway for fun. Whether it's to a kids room, game room, wine cellar, etc. (Below: twist the pool cue to open)

But 75% are for security. Especially for a wealthy client, they understand that if they are on vacation for a month, a criminal would have plenty of time to break in, find their standard safe and get the tools from Home Depot they need to crack it.

With a hidden passageway they never find it in the first place. Here's a fun video you might enjoy! Feel free to reach out with any questions. We love new ideas!