I presume your limitations are due to the drag drop file handling on the upload from computer?
I did something recently like this and ended up with an ugly "Select file" button when people are in IE.
I really hope IE are pulling their fingers out with IE10, it appears they are. We are getting a load of adverts in the UK now on Microsoft products, like Bing etc. It seems to me they are taking it seriously again.
Actually the drag-drop isn't as big of a deal as cross-domain message passing. We'll likely end up having to use a flash fallback or similar, but last night as we were hacking on this we decided to punt for a day or two
I was actually really surprised when I discovered this when developing the bulk upload facility I did. It wasn't great when 9/10 computers in our office are Macs. Didn't make it worthwhile showing it off to people in our place!
I'm sure they will all support it soon enough and my days coding it will be worthwhile.
Is this considered okay again? Best Viewed in [Netscape 3.0] or [Internet Explorer]