I had this very same idea a while back. The trick would be to get the scope mounted securly and precisely back to the same position everytime. There are some quick detach rings on the market, but I'm not too sure how secure and precise dismounting and remounting would be with them. Also, you would need a scope with accurate and repeatable adjustments because obviously your zero settings would be different with diffferent rifles and loads.
One option I just came accross is the Nightforce Unimount system that attaches to a picatiny type base and always remains attached the scope. This looks like it would do the job.
I'd say use steel picatinny rails on the rifles and get some warne quick detach rings. Considering you'll have to re-sight the scope everytime you switch back and forth, you may find you end up leaving the scope on one rifle while you start saving for a scope for the second rifle.
I do this with my AR's. I have three that I switch back and forth on. I use the GG&G Accucam mount, and have found that it returns to zero every time I remove it and replace it. I've also gotten one for my bolt guns that have rails, but haven't used it yet...
All my 700's are set up with Leupold's QR rings and bases.(not QRW's)
I am constantly switching scopes between guns. I also use a dedicated higher powered scope, just for load work up, in QR's. If you write down the settings for each gun, it'll be real close. When they first came out, I shot a 5 shot group taking the scope off for every shot. They work.
I have also went on far away hunts, and took another pre-zeroed scope, just in case. Another valid reason for using them.
I was told the dimensions are 133MOA for the outer circle with a thickness of the line 3moa and the dot 6moa. I will have to look at one of the units because the Dot does not look like its 6moa from what I recall.
It can be done but each rifle will have its own ZERO also you be best off with a scope that does not have a zero stop. If you use a tactical base, rings, and a torque wrench 65in/lb it will return to zero.
Example of what I noticed when I zeroed it the scope on my 284 and I moved it to my 308 I need to add 4moa of elevation and 1.25moa of left wind. So in my dope book I made notes of this so when I moved it from one setup to the next it would be easer to re-zero. It work well for the most part but at times it was a pain.