Moon+ Reader does allow you to change the background images and font colours. The dictionary lookup requires you to install the dictionary app, but it works pretty well. It isn't quite a one tap lookup, it's more hold and then correct the selection before tapping to select dictionary lookup.
Moon+ Reader also offers the ability to sync progress to Dropbox, though I've never got it working to read that progress on another device to keep it in sync. I suspect that I'm missing something though.