I just sold a bunch of stuff and parted out my long range precision build.  I am down to only 3 essential ARs: 9mm A2 SBR (SU-WEE-TAH!), M16A1 clone and a clean-looking Bushmaster M4-gery.  Now, since I am getting into silencers, I want to start a new SBR: A1 upper, with superlight 11-inch barrel and a special new phantom flash hider for the AAC M4-2000 silencer.   Does this kinda make sense for a suppressed carbine?

Any ideas on where to get such a barrel?  

I heard there may be reliability issues with a shorter barrel.  Can anyone comment on that?  

Perhaps someone could post a pic of their suppressed 11-inch setup?  I would love to steal some of the ideas!

Unless you already have the A1 upper , why not a Flattop? - more versatile.
I would rethink the Superlight , with a shorty you're not saving much weight, and
heat transfer/stiffness is better with a heavier barrel.

Lot of posts here with 10.5" SBRs , even FA guns - you will get some back pressure
with a suppressor , so should be reliable cycling.

Model 1 sales has E. R. Shaw   7.5" - 10.25" and 11.5" barrels - plain or chrome lined.

www.model1sales.com/item-detail.cfm?ID=BPI150&storeid=1&image=barpistol.gif&CFID=2080280&CFTOKEN=78326869

edit - I have a 7.5" AR pistol BTW , functions great - just need the correct size gas port.