Request/Idea: Multiple Attribute <select> Category in mod_virtuemart_product

[lipes]

Hi. I want to request if is possible to add an Multiple Attribute Selection of the Category's in the Virtuemart Product Module...
example: ( http://www.w3schools.com/tags/tryit.asp?filename=tryhtml_select_multiple )

We can only select 1 category to display the products in our page....
It will be nice if we could choose/select more than only 1 Category:
- To show that Category's products that we want..... (ex: "Category A", "B", "F")
or in the other hand...
- Or by choosing the Category's that we dont want to display that products ... (ex: "Category C", "D", "E")