Design of iPhone productivity app

I am looking for a graphic designer to design the main screen of an iPhone app. I have the first layout ready and now want somebody with taste and experience to prepare the final graphics. (I will send my sketches of the layout to the successful bidder). It is a calendar/scheduling app that lists four types of items on the main screen and allows to drag and drop some of them. I would like to work in two phases. 1) First phase involves preparing 3 concepts of the design. One graphics for each of them is enough. I would like them to range between something very much based on the regular iPhone design (example: [login to view URL]), through something in the middle ([login to view URL]) to a purely new design ([login to view URL]). After completion of the first phase, a 50% milestone payment will be released. 2) Then I will select two designs that I like best. It can be either two selected from the first stage, or one plus some modification of it. I will ask you to develop the full design with all the pieces of graphics that are required to build an app. The rest of the payment will be released after successful completion of this stage. Please treat the above examples as a suggestion of the design level that I expect. The design should fulfill the Apple's conditions concerning the apps submitted to the Appstore, particularly the "iOS Human Interface Guidelines". Please include a portfolio with your bid, otherwise I will ignore it. Please feel free to ask additional questions.