My build would be simple;
Sako TRG 22 (in .308) or 42 (in .338) with a Leupold Mark 4
Pretty much nailed it.
Sako TRG in .338 lapua is my dream gun.
And if money were no object, I'd just build a standalone sentry gun like in the movies. Except mine would have Night vision/Thermal imaging, automatic sighting adjustments, remote control firing from my cellphone, and fully automatic.
Why take just 1 shot? Let off a few before the first one hits.
And don't worry about what I'd use it for...