I don't have this cart...yet
...but, like you, I was trying to figure out what else I could use it for...So far here is a list of ideas I came up with:
1-Cupcake wrappers (of course)
2-Crowns/hats (Make a crown for the people/person you were having a party for, or make a crown for a baby doll, etc.)
3-Candle decorations (we all have candles that we never light-if you have a white pillar candle I think it would look nice to just change the wrapper to match the seasons and keep the same candle - or give as a gift)
4-Cup wrappers (if you're having a party with paper/plastic cups and you're tired of writing names on them with a sharpie...make a few wrappers in different colors or different designs to decorate the cup so that everyone knows which cup is their own - this works great for a kids party if the kids arn't old enough to read yet, they could easily say 'my cups is the one with the blue stars!' and I'm sure adults would love them too!-I know I would!)
That's all I could come up with, but I REALLY like the lamp shade idea! In fact, if you wanted to, you could probably hang some from the celeing in a pattern to make it look like a chandelier. For example, hang 10 in a circle using 5 inches of string, then hang 5 more making an inner circle using 7 inches of string and then have one hanging in the middle at 9 inches. I can see the effect in my head...and I can envision it as a pretty fancy decoration, but many ideas that start in my head typically sound nuts to other people. So, you can take it or leave it
Well, I hope this helps. Have a great day!