Well this barrel looks
http://www.jgsales.com/mega-arms-5.56-ar-15-barrel,-18,-black-nitride-melonite-finish,-1:8-twist,-new.-p-70984.html
http://www.whiteoakarmament.com/xcart/product.php?productid=17824&cat=250&page=1
http://www.fulton-armory.com/barrelfa20nmhbarss1x8plainmuzzle.
http://www.fulton-armory.com/barrelfa20nmhbarss1x8plainmuzzle.aspx
http://shopwilsoncombat.com/Wilson-Combat-Match-Grade-Barrel-223-Wylde-Super-Sniper-20-1-8-Twist-Stainless/productinfo/TR-223SS20NF-18/
https://www.primaryarms.com/Odin_Works_18_223_Wylde_Barrel_3_Gun_Profile_p/b-223-18-3g.htm
https://www.primaryarms.com/Odin_Works_18_223_Wylde_Barrel_DMR_Profile_wit_p/b-223-18-dmr.htm
I realize this is not 100's of choices, but these barrels seem pretty good value. They have the specs u needed.
If I am not on the right track, I'm sure someone chime it!
Tony