First lets get the links out in front. Caleb wants a scout rifle that takes AR mags. Steve over at The Firearm Blog had visions of it, Tam ran with it, and http://www.saysuncle.com/2009/06/26/stuff-i-dont-get-small-caliber-scout-rifles/said to do it with a real caliber.
I personally dont understand what is wrong with that Remington pump Model 7615 It takes AR mags, it even has a Tacti-cool Knoxx stock.
But onto a bolt gun idea, Caleb talked about Mausers this morning, and I remembered my own plans for a Scout Rifle. The German Army made 'trench magazines' for a very short time. They were 20 round magazines that installed into you Mauser bolt action and loaded from the top with stripper clips. There is a listing here. This would allow you to use any cartridge with a case head similar to the Mauser cartridges, this would include anything in the 308 and 30/06 family. My personal choice would be 7mm/08 or possibly 358 Winchester. My idea was to build a short scout rifle around this magazine. It would not be detachable, which makes for a hunting problem, but I was planning on solving that problem with a block of some sort, or another magazine. A Leupold 4x scout scope. Follow this with a good quality synthetic stock and we are set. In Texas hog country I would put a small piece of rail on the right side to mount a flashlight and it would be set.
Upon reflection, I think it's time to start thinking about this rifle again. Good thing my wife loves me.