If you want the option of sending people real (printed) Gift Vouchers then I'd run them as two separate products.

Product A would be a nicely printed physical Gift Voucher, with a weight attached to it so it would be a non-virtual product with a shipping address and shipping charge (to cover your printing and postage costs). If you don't have a physical shop and they stilll have to use it online then set up a Discount Coupon for that amount and print the Discount Code on the paper Gift Voucher. Make sure it's set up for single use only.

Product B would be an e-Gift Voucher with no weight, and no shipping charge.

The problems that might arise would be if you had an online shop and a physical shop - keeping track of the use.

Vger