Hello, my name is*****'m a sound engineer, I specialize in many different audio components. As far as getting one that will fit cosmetically, those systems are a thing of the past. You're not out of luck, there are still plenty of compatible turntables out there, so you have an opportunity to upgrade.
Choose any turntable on the market, based on size and color that you want. The only thing you need to look for is whether it has a phono/line switch. Older turntables didn't have a phono preamp built in, so your JVC system has the preamp. It requires a lower signal, so a line level turntable won't work, it will be distorted and burn up your built in preamp.
Click here. Notice the back of it says phono output? That's what you're looking for. Some will even have a switch like this, click here. Either of these types of turntables will work with your system. As long as it doesn't use a line-level output, it will work with your system.