For the ultimate I'd consider the Titanium Strata from Rifles, Inc. They cost $1000 per pound. It weighs 4.5lbs. The list price is $3300 but you need to supply the Remington 700 Titanium action which, I think, will run you about $1200 for a total of $4500.
I'd then put a Leupold 3x9 ultralight scope on it with a custom varminter or horus reticle for longer shots w/o dialing. That will add a little over 1/2 pound. Total weight would be just a hair over 5lbs.
If you are planning to reload, I'd get it in a 7mm wsm
and load 168 gr. Berger vlds.
If you're not going to reload, I'd get a 270 wsm and shoot remington 150 grain accutips. I've had really good luck with these long range in my tikka 270 wsm's.