Go to a furniture store that also carries recliners (apart from one that only does) and talk to them. You might get a 'davenport' - a sofa that's a kind of platform, possibly that the legs unscrew from, with a slab of foam on top where the sofa back folds flat directly onto the seat part (and the sofa back frame piece folds back to become a sleeping platform).

Most sofas are wider than the average doorway--to get them in the room, movers usually tilt them up on one end and move them in vertically at an angle. With a 29" doorway, you could probably get a sofa a bit wider and still get it in the room. The interior doors in my apartment are 29" wide and I have a 35" deep loveseat and a 40" by 36" armchair that did have to be tipped up on end to get through the doorway, but it wasn't hard. Also consider taking the door off the hinges on moving day, as that usually gives you at least another inch of room.

Also consider sectionals, where the individual pieces will be smaller and you should be able to tilt and wiggle them through the doorway. You'd need to choose carefully, but you can get two sections that put together look like one sofa.

Other options would be to get a loveseat, because it is not as long and therefore more likely to fit vertically through a doorway. Or consider armless furniture, as the lack of arms will make it easier to tilt and manover through doors. And some sofas have legs that can be removed for moving and then put back on, making them easier to get through doorways. You aren't going to be able to get huge, bulky overstuffed furniture into your place. But you aren't limited to futons or reclining sofas, either. Just check with the place you buy your furniture from to make sure they will take the piece back if it can't be carried into your apartment. And then find something you like.

I'd go to a few different furniture stores and ask about sofas that can get through tight spaces, instead of focusing on the depth of the furniture. Experienced furniture sales people should be able to point you to lines of furniture that are suitable for your needs. I live in an older city with lots of tiny apartments with narrow, twisting stairways. All I have to do is mention where I live, and salepeople know exactly what I'm talking about and have a good idea of what will and won't work in that type of building.

Thanks for the info!