Unless S&W has plans on an X-frame 357, you may have quite a while to wait. The 500 S&W Magnum may be the only frame out there right now that can hold 9 rounds of 357 in the size of its cylinder. A 4 round 357 may be too small unless they modify or copy the old COP design of years back, a 4 shot 357 Magnum "deringer".