I happen to collect these cars. I have a number of them (20+) and have tried to keep the collection to 1/24 scale, like yours you have now. I got most of mine from ebay using the searches "glass car" and "crystal car". There are nascar versions of these as well. I have a testarossa, porsche 911 type, cobra, TD, gullwing, grand sport, etc. These are pretty cool as most of them are frosted in the underside showing seats, engine, spare tire and what not.