Self-serve online design for print

We design and print calendars for organizational customers. We create several basic "master-designs", each with space for individual customers to insert/add their own ads and promotional material. Each customer receives a template, adds their own information in the designated areas then returns it to us. We add their info as a top layer to our existing design, and then print and mail. Our goal is to create an online platform for customers to be able to layout and design their customized information, i.e. create their entire customization 'layer', without the need to hire their own graphic designer. So we need a webpage that will do the following: 1. Customer uploads and maintains various graphic files (PNG, JPG, TIFF, PDF), which are all displayed on a list. 2. A "design area", and a selector which will allow the customer to choose which page of the publication he wishes to work on. When chosen, the corresponding page would show in the design area, plus guides, so the customer knows where to put his graphics. 3. Customer is able to place one or more of his uploaded graphics into the design area, which will now show on top of our pre-designed graphic. As well, he can add a line of text. The customer can then then drag/ move, resize, rotate, recolor, copy, cut & paste all those added graphics. 4. We will be providing a table with where there should be ruler-guides. We'll need some basic snap-to-guide and resize-to-guide mechanism so the customer is aided in fitting his graphics into the proper areas. 5. Once the customer is ready, a multi-page PDF is generated from all his customization and uploaded to the server where we will process it for print. 6. The customer needs to be able to save his work, edit and re-edit, do and redo, as needed until he is happy with his customizations and is ready to approve and go to print. That means that the unfinished files need to somehow be saved on the server to be reloaded later when the customer is ready to continue. 8. The final product (PDF file) needs to be press-worthy. It is vital that the graphics aren't degraded into low-res in the process. Vector graphics and text need to be preserved as such for quality (i.e. not rasterized). 9. Existing parts of our customer system, including a system to combine our master layer with the customer's layer, are already written in vb.net / webforms/aspx. Our database is MS-SQL. The system needs to fit in with our existing system so that it can be maintained by our programmers. (Though we've been using vb.net, other .net languages would work as well). We host the system on our own servers. We have come to believe that we need to be using SVG, and not canvas elements. This preserves the quality of the graphics, and also can easily be saved on the server (it would need to be saved together with the embedded graphics ... perhaps in base64?) We have awarded a similar project in the past, but unfortunately it has not completed. Please only bid on this project if you are serious and have the necessary skills.