I'm just going to throw 2 things out here that don't answer your question.

#1) Nothing is as cheap as drywall
#2) Why do you want something different? - is is durability, fear of chinese toxins? Does it need to look as good as drywall?

If you are looking for durability - wood makes sense.

Not looking for something as cheap as drywall just something that comes even close. We want something different for reasons of total moisture and dust control.

You can buy 4x8 sheets of beadboard plywood either 1/4 or 1/2" thick and paint it to allow moisture to pass or not.

You could also tape drywall without sanding and apply a vinyl wall covering.

You could also use pre-finished vinyl covered drywall.

Foil-backed drywall or a polyethylene sheet behind drywall will act as a vapor retarder.

Anything you use will create some kind of debris when it is cut.

Thanks for all the answers macv. We are not concerned about the dust during installation as much as we are concerned after. When painted drywall is done it collects dust faster than slick plastic like the kind in bathroom which is what we are looking for or something similar and painted drywall doesnt stand up to repeated moist cloth wipe downs as well. If we have to go with drywall then we will and it wont be the end of the world but just looking for something made like the plastic/fiberglass stuff you see in restrooms in commercial applications.

" painted drywall doesnt stand up to repeated moist cloth wipe downs as well."

It does if you use the right paint!
Semigloss in our bathrooms has held up very well. (You are talking about bathroom walls, right?)

I've designed a lot of commercial bathrooms and they had semi-gloss (sometimes epoxy) paint on abuse resistant GWB or CMU or these substrates were covered with ceramic/stone tile or solid surface materials (Corian, etc), or vinyl wall covering. Plastic paneling scratches too easily and has really awful joints.

You have opened up my eyes. I have done some research and will do more reading. I will talk to the wife about different painting options for the interior house walls. As far as the bathroom goes then yes we do want the plastic panels close to the shower but it sounds like maybe we can go regular drywall there as well with the right paint applied.
Thanks

In our area, it's required to have drywall with a tape coat before any other type of wall panels/type. If you come up with an alternative to drywall, you might want to check in with your local building dept to check out the requirements in your area.

Semi-gloss paint on GWB sometimes shows the imperfections of the taped joints. Blueboard (veneer plaster system) is a uniform hard coating with no flaws and holds paint well. Unfortunately it is not available in all parts of the US. It can't hurt to ask if it is available. In my area it is the standard finish and also the cheapest.

Well we took a trip to town and looked around and a long story short...I LOVE drywall. The prices of all other alternatives was from twice as much up to six times as much. Thanks for all the helpful tips and advice.

I remember reading about a drywall that did have a paper cover and therefore resisted mold etc when wet. It was of course more expensive than drywall but I may look into it for the bathrooms and kitchens when we build. Good luck!!

It has fiberglass faces and a special taping compound is used.

It cannot be used behind tile in showers, etc. that would be DensGuard or DensShield.

Here is a link that might be useful: DensArmor