You have at least two options:
a. costy but very nice - Near Manufacturing, check out www.nearmfg.com.
Superb machining and finish, true Picatinny specs, sweet. Fit like a glove. Deal direct with Richard Near, address on website.
b. very reasonably priced and excellent machining and finish. Not mil-spec so not as many cross-slots since they are on 1/2" centers. Hollowed out underside, should be bedded to receiver for best fit and performance - simple to do and instructions with the base. Past concerns with screws breaking, this has been fixed and Ken Farrell is a great person to talk to and deal with. Check out http://www.kenfarrell.com,
you can order from the site.
Brownells might have others. Heard that Badger is going to do Savage bases but nothing on their website yet - might have just been a rumour.