Downtube friction shifters for 11 speed I'm planning to build a steel lugged frame and equip it with downtube friction shifting. My question is:


Do Dura Ace 7900 downtube shifters come with friction mode? The left lever does not have a D-Ring for switching between SIS and friction mode according to my observation.  If not, which model of Dura Ace shifters offers friction mode?
Do downtube shifters have a predefined shifting cable travel so that the older DA friction shifters could not be used on 10 or 11 speed cassette simply because there is not enough cable travel?
Apart from Cane Creek, are there other manufacturers who offer aero brake levers?
(a) Friction is gone on the right on 10/11 sp dura ace (they apparently save a spring while doing this, which probably simplifies things a little bit aside from interest in this). Microshift BS-T10 bar ends are 10 speed, front friction with rear switchable, and you can probably mount them on the downtube with a bit of work.

(b) Other friction shifters should be fine. 

(c) SRAM among others do. 

I'd think going with a 9 speed system may be easier (you can find Dura Ace SL-7700 shifters with index+friction for cheap).