As near as I can tell with Mosaic, you'd still have to make some
changes. Unless the content type is text/html, it just doesn't
get displayed on the document window. Even so, I think you're still
a far stretch from having the same effect as x-exec. For instance,
you need at least a server to drop these application/x-exec
documents on the browser.
I could be wrong, but I certainly can't figure out how to replace
x-exec: with application/x-exec. If you know how, please show
me.