I think you need one of these police surplus 457s mentioned in this thread: Used 457 on the way...

That way you'd have plenty of money left over for sights, ammo and holster and could have fun with a project gun getting it just the way you wanted. The commonality of controls and similar size to your 3913 makes this a natural choice, and you can spend as little or as much money on "building" an ideal CCW.