Wouldn't you still need to use VMs even if IE were available for Linux? Aren't sites supposed to be tested for browsers and platforms? E.g., a site may show an undesired behaviour under Chrome for Windows but not under Chrome for Linux (or vice-versa).

N.B. not a web dev, so please put me straight if I'm wrong.

You can actually just go grab the wms from MS of modern.ie the only limitations is that they can't run for more than one hour.