Hard to beat a 30-06.
Any of the Remington Mtn rifles in a Ti or Edge stock will do the trick and will come in just a little heavier than a Montana. I've got a 700 SS Mtn rifle in an Edge stock in 30-06 that weighs 6lb 13ozs with 3.5-10x40 Leupy. Depending on budget those two are probably your best bets under $1000. I've got a NULA but you are talking more money there. Rifles Inc and a few other make lightweight rigs too.
No need for a Magnum but if you do, one of the 300 wsm/saum or 7mm wsm/saum would be a good bet. A 30-06 will kill anything you need though short of big bears (and it has done that too). A 300 WM or a 7mag will certainly be nice but not needed and come at the expense of recoil and powder.
