Repeating fields - similar to tickets

Hi,
the tickets feature is really useful, but a similar field set would be useful for other items often sold with event registration.

As an example, many registrations sell a t-shirt so it would be good to have a repeating fieldset which allows variables such as t-shirt size, sleave type etc with multiple quanities.

ie.
Size: XL Sleeve Length: Long Qty: 3

This would be very similar to the ticket option.