Thanks for the information provided so far in this thread.
This feature would be a good addition to WooCommerce, either as a plugin or as an enhancement.
My current client sells e-books directly to customers and refers them to another vendor for a print version. It would be helpful to put both cases into a variable product record.
For now we are working around the lack of an “external” option in variable products with this approach:
(1) Disable the “Add to cart” button by setting the print product as “out of stock”;
(2) Use the short description field to give a link to the print vendor’s product page;
(3) Add a CSS rule to suppress the display of the disabled “Add to cart” button.
