If a standoff missile is being considered by anyone for a regular FS campaign (that is, in the FS universe), the issue of it being shot down close to a target ship would be a problem. One could get around this by designing such a weapon with a stealth flag in mind so that it can't be targetted as easily. All you realy need to do is make a mini stealth craft with no cockpit or weaponry (... well, maybe mini-turrets), and use the ships editor in FRED to give it a kamakazi AI and special explosion effects, then have them launched from a docking bay. Another launch method would use the more universal docking abilities of SCP to have it docked to a bomber that has a belly dockpoint. When it undocks (ordered by scripting) give it the ai kamakazi sexp from SCP. This could pose a problem if you want to have the player's bomber able to launch one, but you might be able to use training commands so that when the player hits the key (or key sequence, or button from a stick) that calls for a support ship, the missile is scripted to undock, then the rest goes on as above. I'm not sure if that made any sense, but there it is.
Later!