App Mockup for Future Product/Web Service

We're looking to create a mockup for a web & mobile app that will need the following: -Logo (we're not looking for logo design, but something unique and useful for the mockup) -2 app mockup screens in both iOS and Android design languages (total of 4). Each mockup screen will be the same, just specific to the OS. -1 additional mockup of app functionality in the Android notification pull down bar. -Web interface mockup. -Mac OS taskbar icon mockup that resembles logo and has a drop down menu with specified options. We already have small, general, non-artistic models of the screens available to help ease into the work. We need someone to help us make it beautiful. Should the project advance, we'll be looking for a greater emphasis on our design language to make it consistent. A non-disclosure agreement must be agreed upon for this project.