Barnard, NZ - also comes with their excellent match trigger included, no safety tho.
Stiller, US
Lawton, US
BAT, US
These are are the main players, but there maybe others such as EDM etc but im not sure if they will sell just an action.
They are all priced about the same, you can check their respective websites for pricing and delivery times - you might be best off finding a gunsmith or dealer that already has an action in stock or you will most likely have to wait quite a while to get one.