Tents without zipper door?

I was wondering if there are any tents still in production that don't use zippers for the door(s)?! For example the RMW Bombshelter appears not to use zippers for the door. Thanks for any help/information.

This is a pretty good question. I had a North Face tent back in the 1970s that had a tunnel door with no zipper(and this was before the arrival of full length vestibules.)

Whether someone makes a tunnel door now(for snow)is up for grabs. Somebody will know.

The best expedition tent I ever used in many respects was the Gerry Himalayan. It had a tunnel entrance on one end and a zip entrance on the other. Besides the fly on the outside, it also had a frost liner (in other words, triple wall), so that condensation was kept out of the "living" area. The two vestibules were separated from the main tent by a small sill. Both vestibules had floors with zipout holes. We generally used one for the snow for water supply and the other as the "human waste" hole when we were stuck in an extended storm. The tent was heavy, but it was a 3-person tent, so not too bad when split 3 ways to carry. Unfortunately, Gerry got subsumed by a large conglomerate, which got bought by another, which got bought .... well, you know the story.

The big advantage of a tunnel entrance, even when you have a vestibule, is that entering and leaving in storm conditions reduces the amount of snow/rain that gets into the vestibule, some of which inevitably gets into the main tent.

You can still get frost liners for certain expedition tents, though they do add weight, and they aren't as much of an advantage as they were with the old-school tents.

A few of the Exped tents I think have zipperless designs, The Vela I (which I have and like) has no zippers, instead there is a kind of cord you can pull and tie to open up the vestibule.

I don't think the Appy Trails tents use zippers.