You could try the matte photo paper. Since it has a little texture to it the stickers may peel off easier. I think the glossy paper might be too smooth.
You could also try slipping a regular sheet of paper into one of those clear vinyl protective sleeves.
Unfortunately, if laminating didn't work then there's probably not much that you can print/write on that will allow them to come off. Sounds like some really sticky adhesive.
You could take Crystal's idea and modify it a little if you don't have a magnetic board. Instead of magnets you could create "buttons" in whatever style you like and use velcro. Or stick with the magnet idea and keep the paper on the fridge.
Another idea would be (depending on how your reward chart is set up), if the check boxes are near one of the edges of the paper you could use the binder style paper clips. You can decorate them by attaching butterflies, flowers, whatever, then she puts a clip by the corresponding box.
One last idea would be to create little pictures of whatever interests her as your "buttons" and get some of the repositionable adhesive tape used for scrapbooking to put on the back. Then they could be peeled off and reused until they loose their adhesiveness. (LOL, is that even a word?!) That would probably work really well with your laminated paper. You could even laminate your "buttons" then you'd just have to put on some more tape when they would no longer stick. Anyway...
Let us know what you come up with. I'm tired of reprinting them each week myself...