C-H /eaton has been selling a 2-pole with 2 singles of either 15/15, 20/20 or 15/20 for about 2 years or more. And they happen to work very well for remodels.
On the 2 wire circuit idea, I have to agree, it is a waste. There is no more danger, or loss in circuit quality in them than any other circuit properly wired. And with copper prices doing the hoochie choochie, it makes more sense. Environmentaly, they say that 50% of the earths copper is mined out now, and that in the very near future they will have to resort to Trash mining! (For that and other resources...) Kind of retro-active recycling....
