PCI express slot divider


Has anyone seen PCI express slot divider

single x16 to four x4,

single x16  to two x8,

or something similar.

I don't think that is possible. Because each slot is set up on its own lane to connect to the CPU I don't think you could divide it up like that. I believe it is only one device per slot. 

Today I was looking for pci express  extender and found by chance this http://www.aerocooler.com/product_info.php?products_id=2513

a riser, not exactly a splitter.

than why it has one input and two output ?