Looking for replacement vinyl tops

[Y2KGTA]

I have tried to search the internet for a company that sells replacement vinyl tops. What I am looking for is the one that is basically a fiberglass or plastic shell and has the vinyl on it that simply fits over the roof and either snaps into place or uses epoxy to hold it on. There is no seaming or anyything to do, it is made to fit the car. I have seen them offered for sale before but I do not remember where. If any of you have seen the episode of Pimp My Ride with Big Ron's orange Eldorado, thats exactly what I am talking about. I am looking for a replacement for an 83 Riviera. If anyone can point me in the right direction, that would be great. Any help would be appreciated. Thanks