This is what the MCS-BDL mini chassis is
Its not an action, just something you attach your action to. And it included the bottom metal to take higher capacity magazines.
I think you misunderstood my comments on the Savage. Its mainly the barrel that needs to be changed out. If you get a Model 10 or 12 the factory stock might be fine. If it has a tupperware stock, then you need to replace the stock.
If you start with a factory Rem 700, then you probably will replace the trigger, stock, have the action and bolt machined to straighten them out, send the action to a smith with a barrel blank and expect to pay at least $550 up to $700 for a barrel to be machined to headspace on our action cut to fit your action threads. So I would say that typically very little of a Rem 700 gets re-used.
Thats the reason why it is usually a better idea to go straight to a custom action if you like the Remington action. Nothing needs to be thrown away or "fixed", so you just have to add the trigger, barrel and stock.
Jim at Northland Shooters Supply is selling Remington fit barrels from Criterion or Shilen with a standard shank and his own precision barrel nuts. These will fit most of the clone 700 custom actions and again, you can buy a completely machined barrel for about $350 as opposed to $550+ and install it yourself. Some refer to this configuration as a "Savington".
If you look at Pierce Engineering, they do actions for tube guns and they sell the tube gun chassis system too. Its all a question of what you want. I spent a lot of time on Remington rifles (relatively new ones) which would not shoot until one "fixed" a bunch of problems and ultimately one seldom gets around the need to replace the barrel, by which point one is well into custom gun money. Initially I was skeptical of the Savage as it just feel like crap compared to a Browning or a Ruger, but I have to say that they are pretty good shooting factory guns without needing any voodoo medicine. I have a model 10 223 with a 20" barrel that shoots 75gr match ammo in 1/2" effortlessly. It cost me $550. I have a model 12 243 that I recently fitted a Shilen 26" 8 twist 243 AI barrel to and it shoots 1/2moa at 200 yards (shooting Berger 95gr bullets). I paid $770 for the rifle and later added the match barrel with the 8 twist that Savage won't sell us. I recently took my first coyote double with it.
Right now I am building a 6.5x284. Its tricky in that it needs a real long action. This last weekend I found a donor Model 111 (was a 270Win) which I bought for $285. It was a DBM version. I ordered a $190 Hogue stock for it and have another 26" Shilen barrel on order. Including the stock and barrel, I will have only $825 in this gun. My initial 100 brass shells, 140gr bullets, primer and powder and dies will have cost me nearly 1/3 of that...