I would love to get one of these. They aren't made anymore, but they are SWEEET!!! I've found good ones chambered in the odd savage rounds, but those aren't common rounds. If you ever, EVER, find a model 99 in .308, you'd better buy it right freaking now! Then put a military style sling on it and one of those small scopes that mount far out on the barrel away from your eye, and you will have absolutely the very best all around rifle there is in the world, BAR NONE!
The Savage 99 sure is a sweet rifle. My uncle owns one just like you describe; I forget the variant but it was probably one of the last made in .308 with the rotary magazine. All the more recent ones have the detachable box magazine; still a fine design but not quite as nice, IMO, as the older integral magazine.
You're right, they are scarce. Savage made a run of 99s just a few years ago (some company anniversary, I think). I wish they'd put it back into regular production, but it is one expensive beast to machine (compared to the bolt actions). The only examples I've seen at gun shows for several years now are older models with hefty price tags - and usually chambered in Savage .250-3000 or some uncommon caliber.
I'd never thought of putting a "Scout" scope on a 99, but that should be a nice combo indeed.