[Greenbuilding] flooring conundrum

[Chris Koehn]

I have a question for the group:
I'm doing reno's on a 1975 home my family purchased on Vancouver  
Island, and I need to make some decisions about flooring.
  It's a straight up international style home, emphasizing saltwater  
views. I tore carpet out of the 14' X 20' living room (we recycled it  
as padding in our timber framing shop) to find a wiggly plywood sub  
floor, with an inch of height variation overall. (I've confirmed that  
the variations aren't symptomatic of any structural concerns: one  
area is due to a badly crowned floor joist, and another area is  
caused by joists bearing on a poorly executed masonry fireplace).

For a variety of reasons, fully correcting these conditions isn't  
feasible. Variability in the sub floor is as much as 1/2" in 3' ,  
making localized leveling inadequate.
I've considered correcting the dips from above with self-leveler, but  
this isn't practical either, as one wall of the room is patio doors,  
and elevating the floor level (to a level plane) would actually bring  
the finished floor level well above the threshold.

  I had intended to install a walnut floor, milled from a yard tree I  
took down years ago, but I'm afraid the out of level condition makes  
hardwood out of the question. So I'm looking for ideas and options.  
We would prefer to not use carpet, though I'm beginning to think it  
might be the best option, at least  in terms of concealing the wiggly  
condition (any good enviro carpet options readily available out  
there?) Can anyone recommend a specific cork product, given the  
installation?

Thanks in advance for any advice!

Chris Koehn