you can buy aftermarket ones already done but what i do is go to HobbyCraft and have a look on the shelf doing jewelry for the coloured wire.....comes in all sorts of colours and is pretty cheap, black is obviously an useful colour......make the dizzy from some small tube such as the plastic bit from a cotton bud only needs to be a few mm long.....paint the bit of tube black.......cut enough length (as in a V8 would need 8 + 1 to the coil.....although i sometimes miss that one out)....make the lengths extra long.....stuff the lengths into the tube, i tend to get all flush apart from one which i push through then to locate into the engine,.....a few spots of thick ca in the bottom holds it all together....drill a tiny hole in the engine where the dizzy goes and glue it in.....drill out with a tiny bit where the plugs go in the block......do one lead at a time....trim so its a bit longer than you need to go into the relevant plug hole.....spot of ca and push it in so it looks right
i have also stripped down a dead usb cable for its wire inside but it dosnt bend easy to follow the shape of the engine but it does look nice cos you can pick the colour you want, loadsof colours inside a usb cable
hope that helps