SLR Rifle Works makes some of the best looking receiver sets on the market.
The ambi B15 receiver set is not cheap but the machine work that has gone into shows the time and craftsmanship they produce.
SLR also has rails that are specifically designed to fit nearly flush with many suppressors out there Like this Ion lite from a 13.7 barrel from Rosco I am using here.
Its the type of thing you build once and enjoy for years but probably wouldn't do it twice.