Hi Reese!
I haven't encountered any spa locations in Walt Disney World that do nail art or designs myself either.
What I'd recommend is that you check a site like eBay for nail art designs and search for Disney designs there. You'll find a huge variety of ready made decals and 'slide off' nail art. Have them shipped to you prior to your trip and she can apply them herself or visit a local salon prior to your vacation. That way, she'll have them on to enjoy throughout the trip!
Then, you can still make her an appointment at one of the
Walt Disney World Spas for some pampering instead! I recently enjoyed the Mandara Spa at the Dolphin with my daughter. A massage and facial mid-vacation is a lovely way to get re-energized and treated to something special while on vacation. Check out the Mandara website as they often have great special promotional packages advertised online!
I hope you find just the right Mickey Nail art for your wife to enjoy on vacation - along with a little extra pampering thrown in for good measure!
Thanks for visiting the Moms Panel with your question.
Wishing you a Magical time at Walt Disney World Reese!
Kirsten