Honestly you have about everything covered in any case, so short of something that really interests you; nothing you build would offer you anything you don't already have.
Getting a good barrel that is already threaded isn't hard to find. Shaw, EABCO, both are about a $150-200 and will out-shoot most people. The 308 does offer component attraction, and unless you really want to get beyond 1100, the trajectory isn't an issue unless you can't judge distance/dial a FFP scope.
My vote, simply because I'm enamored with mine:
Shaw heavy barrel in 6.5 Creedmoor - $200
Action - $60
Boyds stock - $150
PA 4-14 FFP - $230
GT - $640 package.
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