Leggett & Platt make all of Herman Miller's Eames furniture?  

Curious as to what suggest...
Curious as to what suggest this?

At least some of it is....
as two Herman Miller suppliers: Davidson Plyforms Inc. and Genesis Seating Inc. are owned by Leggett & Platt.
http://www.mlive.com/business/west-michigan/index.ssf/2009/08/herman_mil...

Yeah, those are...
Yeah, those are the subsidiaries I was thinking of (plus other miscellaneous bits of Leggett & Platt, like Grand River Polishing).
Genesis Seating makes the 670 lounge chair and 671 ottoman, as far as I know, and they also seem to be building the ESU. I'm pretty sure that they do the upholstery and assembly of all the rest of the Eames furniture, too.
If that's true, then it's certain that Davidson forms every piece of plywood, and very likely that Grand River Polishing finishes all the metal.
I have no idea whether Noble International/Concept Metal Products (the company featured in the article you linked) supplies any parts for the Eames/Nelson products, but I'd like to know. I'd also like to know whether Davidson's new plastics division, IRT, has anything to do with the polypropylene Eames shell chairs that were reissued a year after IRT's creation.
[edited to fix a typo]

Genesis makes all the molded...
Genesis makes all the molded plywood furniture for HM including the 670 and LCW, etc. I visited the factory while in Grand Rapids a few years ago, it was pretty amazing. They also manufacture all of Cherner's pieces as well.
As for the polypropylene chairs, I can't 100% confirm, but I believe that has all been contracted in Europe through the same supplier Vitra uses. I know that the Swag Leg chair is made over there in the same factory as the Eames chairs, as well as the Swag Leg desk is essentially the same as Vitra's "Home desk" but tagged for HM at their European factory.