Variable number of rows / automatic populate cells

It would be cool if the number of rows could be passed into the matrix field from another node.

For instance I want a matrix like so:

Product Name Price
1 coolproduct 5.00
2 anotherproduct 5.50
3 moreproducts 5.00

But with the number of products being variable and set by some other node. So some other node says:
List your products and you list : coolproduct, anotherproduct, moreproducts

And then you can somehow tell the matrix field to generate as many rows as there are items in your product list (or in whatever array/list you somehow specify.

Another thing that would be ubercool would be a way to get the matrix to auto populate cells. Or if there's already a way to do that please let me know!