Hey there, I registered here to give some information about the real-world replica of Spike's handgun. If you're interested, read on! Pictures are at the bottom.
Spike's iconic gun in the series is a modified IMI Jericho 941 pistol, chambered in 40S&W ammunition. Many years ago, a company called Poseidon who specilizes in Model Gun's, released two seperate kits. One was a solid cast replica of the gun, meaning it was one piece of resin and had no moving parts.
The other, was a 'remodeling kit' made to convert the Hudson Jericho 941 GBB pistol into an exact replica of Spike's. The Hudson Jericho was a gas BB gun that had many metal parts, working slide with Gas Blowback, and was an extremely accurate representation of the real Jericho. The remodeling kit was composed of instructions, a Grip Kit to replace the stock Jericho Grips, and a frame mounted Laser Sight assembly. We never actaully see Spike using the laser sight, mostly because he's far too awesome to need one.
Now if you're reading this and getting all excited, here's where the hard reality sets in. The Hudson Jericho 941 has been discontinued for many years. Infact, the only thing harder than trying to find one of these guns, is finding Spike's remodeling kit, which is also long since out of production, and even when it was avilable it was only sold in Japan. My advice to anyone who wants to undertake the task of finding the two parts to make this gun as I did, is to either know someone in Japan, "know a guy who knows a guy" in Japan, or to frequently check Yahoo! Japan Auctions, where I have personally seen the kits and the gun pop up on seperate occasions. You just have to have alot of patience.
Here are some pictures of the kit that I own, followed by the origional Illustration from the Cowboy Bebop Artbook, and finnaly the completed piece.