As far as I understand it, it's not actually gamestop or best buy or whatevergamestore that decides if they'll set up any display demos - it's all down to Nintendo. It's Nintendo that decides which stores get a demo - if at all. It's been quite hard to even get my hands on a 3DS XL here in Stockholm - and I haven't seen any Wii U demos at all...
I'm on Twitter @DanneSandin!
Furthermore, I think VGChartz should add a "Like"-button.