In the middle of the above thread is a picture of some WTB hubs I modded to make them fit a 165 rear end. I have since done it with a carbon tube that fits over the entire hub barrel from flange to flange. I think the American classic hubs are similar to the WTB's so would be very east to mod. It adds about 40 to 50 grams to the weight of the hub. I have many miles on these hubs with no failures. Dont ask about the bottom bracket I tried to widen though.
Hey, that's my bike...I ran the adapter for 6 or so months through the summer and into the fall, until we had 170 hubs to test and ride. It performed flawless and I still have it tucked away in a box somewhere.
I don't see saving any weight using the adapter and a 135. The weight of the part and bolts will offsetmthe hub weight. Ease of rear wheel removal also diminishes with the 135 spacing.
I would run this if I already had a rear offset wheel. That was the intent of building it anyway.