I found a bezel that will turn a 5.25 desktop bay into 2 slimline laptop bays. $28http://www.slidirect.com/web/do/pub/sku/view?categoryId=10&id=40
You will also need an adapter board for each slimline drive so they will accept desktop ide and power connectors.
These can be had for $2-4 each.
This would be useful for a micro PC with only 1 or 2 - 5.25" bays.