Advice for a husband frantically looking for a nice Christmas gift for his wife.

How nice of you! For a wallet, a Suhali would be GORGEOUS. I love those PTI wallets and really, a mono wallet wouldn't be overkill, I don't think. That was how my dad started my mom on LV..the Speedy 30, Porte Tresor wallet, Cles (keycase) and the checkbook holder.
I really think that the classic monogram pattern does stand the test of time, because my mom has had her pieces since around 1989 and they're still in great condition. The Suhali is a bit newer so it hasn't really been around long enough to determine how long it'll last. However, it's a great quality and I think it'll be perfect.