What handguard for Mega billet upper receiver?

[Lonehill]

Got my Shilen barrel in. I want to go with an extended length handguard to cover the gas block. The barrel is Hbar contour and consequently, the gas block area is about twice as long as usual which is fine, but it's got a different finish than the rest of the barrel so I want to cover that up. What's a good solid, lightweight, extended handguard? It needs to have a good barrel nut for a solid setup. Mostly gonna shoot off bipod so I don't want a lot of flex. Is there any such thing as a 15" vented aluminum handguard like Bushmaster uses? Got one on my Remington R-15 standard rifle length though.