I'm looking to build a Dissipator-style AR later this year.

Besides Bushmaster, does anyone else offer a non-HBAR Dissy setup?

ADCO has one.  They are getting them in stock in January.  The ones on their site now are SS, the new ones won't be.  You'll have to email [email protected] for more details.  They come with Mid length gas

http://www.adcofirearms.com/acc/productLine_.cfm?brand=Adco%20Custom&product_category=Barrels


CMMG also makes them with mid, car, and rifle gas.  Their's are medium profile, however.

I've looked at the ADCO, but it looks to be a lot heavier than what I'm after. Are CMMG's barrels/carriers any better than what I'd get from Bushmaster?

Not sure.  I haven't owned either.  They both seem to have a good reputation from what I've heard.

I have one from both.
I had ADDCo lighten a heavy barrel dissy a long time ago.
Steve does great work and I am very happy with it
I recently bought one of the "M4 " type dissy barreled uppers ,which is exactly the same thing but all made by Bushmaster.
Both are great
I love the look and balance of the dissy, its my favorite.
Im not an M4 fan,Love the dissipator and my 20" flat tops.
I own 1 "M4 style" 16" + 2 Dissapator 16s and am building my second 20" flat top.
My taste is currently out of favor, but I dont care.
My dissy's are BM barrels, BCM bolts and carriers,BCM BUIS,LT mounts and Aimpoints ( M2 & an M3) and ive got Magpull ACS stocks with the milspec tubes
and a good stake job on the castle nut that I learned how to do from this site.
I used BM LPK's in a Rock River lower and a Houge pistol grip.
I Would have bought the barreled uppers from BCM if they made them ,but they dont, as far as I know
The bushy barrels have served me very  well for many K of rnds
Just my 2cents

I used to have a DPMS dissy.  IIRC it was a heavy barrel though.  I swapped it with a carbine upper and the weight was noticeably reduced.  

Excellent gun, very accurate, just weighed a ton.

I have a BM dissapator upper as well and have had no problemas with it at all....<><....:)