Thanks for the detailed explanation. I don't think that the fallback will be necessary, as in basically every Kendo UI supported browser, the files will be uploaded in separate requests, when the async.batch option is set to false e.g. IE 7+, Chrome, Firefox 4+. In the case when the async.batch option is enabled, all files selected at once, will be placed in a single list item and will share a common uid, so the current approach won't be applicable.
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI