Online print design tool for an existing website

Have a website currently with Shopify, and would like to integrate a online design tool. Best example I've found online is youprint.com. Must be as simple if not easier to use.. must work on web, and all mobile devices thus I thought HTML5 the best choice but open to anything that would work. (iphone, ipad, android etc) Must be able to design business cards, postcards, and flyers/brochures with bleed... the sample site does this and integration with photo or clipart sites like they have done would be a great addition (perhaps istockphoto, vectorstock etc if any have available api's?) Must be able to import various file formats such as jpg, tif, psd, ai, eps, pdf, png, and perhaps cdr, doc - must be able to tell what color mode and ppi the files are in (rgb/cmyk etc) as we will be working with cmyk Must be able to simply drag/drop elements, type text, rotate items... Tools I need that I have not seen anywhere are ability to setup files for spot uv, foil, numbering, folds/scores or diecuts - if you are not familiar with these spot uv and foil would be the same and needs to create a file for these in 100% K (black) only... numbering would simply need a placement holder, folds would display presets from different folds (like typical trifold brochure etc), scores would simply need a guide line file, and diecuts would need to create a shape outline file or choose from a preset... all of which I could go over in more detail and provide templates for you to use For example most designs are simply two sides front and back, but a spot uv job would require 4 files... front, back, front uv, back uv . Different products would have different sizes, and different requirements ... play with the example site as it does the custom sizes with proper bleeds properly. Bleeds are the area that get trimmed off of a print job - thus for a US standard business card at 3.5"x2" the required file size needed is 3.625"x2.125" (adding .0625 bleed on each side that gets trimmed off) .. also a "safe zone" area which is also minimum .0625 inside the trim area is used to keep art elements away from the trim zones... also shown on the example site. This utility will be used as a link within current site (and ability to integrate with shopify a huge plus)... may like to add ability to allow for custom branding so other sites could also use and the orders would be processed thru our site...or a webapp for mobile If you can do a full or partial part of these requests please let us know how all this can work together in a nice simple easy to use solution... I love minimalist designs and one that a 5yr old could figure out how to use.