Commission an architectural watercolor of their first home or a stylized "family crest" that incorporates their hobbies and pets.
Instead of one nice bottle of wine, buy three bottles of the same wine from different years (a "vertical") so they can host a tasting. what to buy the couple who have everything
A gift card for a high-end cleaning service combined with a voucher for a local private chef. Commission an architectural watercolor of their first home