If you're after a hospitla crib like this one
then just Google images for: "acrylic catering food displays"
Most of these food displays come with a lid and with a little bit of work they can be made to look like an incubator or you could purchase a hot food display that would be easier to turn into an incubator. Obviously if you want a hospital crib for a premature reborn baby then you want one of the smaller food diplays, the premature baby shown above is a 16 inch reborn. For larger reborn babies you will need to find one of the large restaurant food displays, however be warned they don't come cheap.