Advanced form, is this possible?

I've been looking through the documentation, but I can't seem to find a way to achieve this. So I hope to find some good pointers here. I've attached a screenshot of the form I'm trying to make in webforms.

It doesn't have to look exactly the same, but it shouldhave the same functionality. Since the descriptions are in dutch I'll explain it a bit more. It's an order form for customers that they can fill in theirselves (Article Number, Description, Number, Price, Total are the header fields). I know that with the good JS integration in webform I can easily calculate the "Total price", so that's not a problem. But I have no idea on how to make that "grid" of textfields.

Another way to do it would be making 5 fields grouped in a fieldset where users can users have a button [ add another product ] like you see often in CCK where you can add multiple files or something. But the grid suits the use of this form a lot better off course.

Anyone has any clue of this is possible in webforms or should I do this with something else? Thanks in advance.