When Is "Handmade, One-of-a-Kind" Impractical?

It's VERY hard for me to temper my "brainstorms" with common sense. Enthusiasm for the challenge too often overwhelms logic! My latest brainstorm -- an etched medallion or pendant-- is the perfect example. The etching will feature up to 4 user-specified letters &/or numbers. "User-specified" is what makes this creation very special for a customer. The copper disk pictured celebrates a couple's 50th anniversary. But "user-specified" is what will make this item a big money loser for me. Each medallion/pendant requires a handmade template of custom size & lettering. That means creating TWO pieces of art for each customer- the template & the final medallion/pendant, with each process very time-consuming. It's impossible to mass produce such items, even if I could stand to do it. (I can't!!) Dilemma: How can I charge enough to justify creating two pieces of one-use art? Who could afford me? In other words,the custom medallion/pendant I just posted is the best deal ever!