You might have missed, Powdr started a thread a few weeks back, "Rifle rest for accuracy" here in the Gunwriters section.
When I was broke I made mine in the fab shop and added the Protector top, I enjoyed a Sinclair cast steel and a Grizzly cast steel but I removed the windage top..
Midway had the Caldwell Benchrest for $109 before Christmas which is fine for working up loads for my current needs.
A flat bottom rear bag that doesn't roll and wallow and Protector top bags have been a constant for me.