What makes bent plywood "super resource-efficient?" - I'm not challenging your statement, just wondering. I would have also thought old reclaimed railway ties were soaked in nasty carcinogenic preservatives like creosote, is this actually safe?

Apparently we are expected to shell out thousands of dollars to find green furniture. If an entirely green house can be built for a mere sixteen thousand dollars I find it hard to believe that furniture made from recycled materials can cost this much. When did environmental consciousness become a chic fad that we all end up paying for?

I'm curious about second hand furniture- what should one watch out for in terms of materials that will still off gas- I know foam is bad, especially when it's old and starts to crumble... what about leather furniture? If one is reupholstering vintage furniture, what sorts of alternative fibres/foams are there?

So it's pretty much impossible to have a responsible dining set without spending $300 for a chair, then?
Well, there's always thrifting.

Colin had a solid beat on bent plywood processing in this ealier post: http://www.treehugger.com/files/2007/08/wing_chair_by_m.php

To address the above issues:
Bent Ply - Yes it can be very resource efficient because of the way the laminated (glued together) pieces of wood are originally harvested from a tree - via a peeling rather than sawing process. Think of an apple. If you slice an apple into wedges, and one of the wedges has a worm hole in it, you will discard the entire section of the apple. If you peel it, all the way down to its core, you will probably just eat the whole thing, or discard only the tiny holes in the peels, where the holes are. This works the same way with lumber. The bad peels are not discarded but are used for the interior sections of the plywood, while the good peels are used for the faces of the plywood. This process generally saves a huge amount of material.
Also, because plywood is inherently stronger and less likely to warp and shift (because of the lamination process using perpendicular sections of the wood), plywood is also structural at much thinner widths than solid woods.

Railway Ties: Yes - most of them have been soaked in nasty chemical preservatives. Their eco-ness has to do with the fact that they're a reclaimed material. Let's just say I wouldn't eat directly off the furniture here.

Reupholstery and Foams:
Foam alternatives include Natural Latex (which isn't intirely un-toxic due to the vulcanization process - but is better than Petro-created alternatives), Organic Cotton Batting, and using Webbing as a cushion (As in J. Persing's Chair Above). Upholstery - There are tons of eco friendly commercial and home grade fabrics out there for all your upholstery needs. Key things to look for: Recycled content (post consumer or industrial), Certifications (Organic, Green Guard Certified, Cradle to Cradle and others). Some of my favorite cos. carrying eco-friendly upholstery fabrics include: Maharam, Q-Collection, and Designtex. Most large textile manufacturers have eco-selections now, including Carnegie Fabrics and others.

The expensive furniture debate:
As the organizer of HauteGREEN (HauteGREEN.com) I face this question often. The bottom line is that the selection above are tagged 'designer furniture.' Unfortunately, at the present time, the majority of the eco-furniture options available tend to be from either high-end companies who believe they are catering to a niche market, or small - self producing cos., such as J. Persing and Staach, who's products are relatively reasonably priced given that they are producing them on a very very small or even individual scale. Until larger cos. get it together enough to figure out what it means to produce eco-friendly furntirue on a mass scale (if we can do this for office furniture, why not for the home - look at Herman Miller, Hayworth, Steelcase etc.), we can look to these small designers for slightly more pricy options and for inspiration!

One also has to look at the durability of these products! The above pieces are incredibly rugged, extremely well made pieces that are bound to last a very long time with proper treatment and care. Sure one can buy a chair at IKEA for $20, but let me know if it lasts you more than 5 years. Good furniture is an investment which can last you a lifetime. Is $350 too much to pay for a lifetime's worth of use? I don't know?

Used furniture is often the best option, in terms of getting eco-furniture at a value. There are plenty of places to get these pieces, from the curbside, to craigslist, to the salvation army, to salvage and antique stores. By the time you buy a piece of used furniture it should be done 'ofgassing' for the most part. That doesn't mean its safe to eat, but it should be relative inert for any home or personal use. Used furniture is for the most part no better nor worse than buying non-eco-friendly new furniture, so apply your same criteria to to your used choices as you do your new ones. Just be aware of things like peeling paint on really old pieces (as the paint could be lead based etc.).

Thanks again Collin for the great suggestions and check out Treehugger's Green Guides for more info on buying furniture etc.