Buy a Stevens 200 and sell the barrell and stock on a local forum for $100 and go from there. Wal Mart has them pretty cheap the last time I looked just make sure you don't get the Axis/Edge.
If you plan to build a rifle, then any savage action will do except the axis/edge (not the same as other savage rifles). As recommended before, if you can get a Stevens, rebarrel it, buy the XLR for it, then a new trigger and youre GTG.
Savage does sell just there actions in long and short. They show it in there catalogs. What you need to do is contact them directly or through a gun shop either way you will need to have it shipped to a gun shop for the 4473 paper work.
Cheers
505Gibbs