Something in the .45 family and a little like this
I can show you where to go to build a good solid fast twist 45 or even a 40 for a heck of a lot less. I love the Swinglocks but those are in the $4000 range now.
You can build a very fine SML on a Savage target action or one of the new Rem Ultimates for around half that price including a top shelf stock. Both will have full locking lugs just like a CF. Those new Rems are basically a Rem 40X action too.