Not a complete upper, but I recently got a Wilson 16" 1/8 twist stainless barrel with the "Recon" profile, on sale at Brownell's. I installed it in a BCM "blem" upper and put together a complete rifle. The barrel does use their proprietary-length gas tube.
The barrel is really good, so far. It posts sub-MOA groups with IMI 77-gr. and nearly as good with Federal XM855 62-grain.
Function is great, with the slightly-longer than mid-length gas tube and an H2 buffer- combines consistent ejection and a soft recoil.
Assembled rifle: