To add to what JD said, the Commander length slide is a nice blend of recoil control, reliability and sight radius. While the Officer's frame will be easier to conceal it will hold one less round in the magazine. Another option for ease of concealment is the bobtail frame. This is a full size frame that has the corner of the frame/mainspring housing bobbed. This eliminates the corner that most often prints and lets you retain the full size magazine. Check them out too.
Ed Brown Products, Ed Brown Custom, rifles, 1911, parts
DW Commander Cls Bobtail