our next SP release for Test Studio will include a brand new feature that will allow you to customize the content of your email results. This will include the ability to have the results in HTML/Excel format so that your recipients won't need to have Test Studio/Runtime edition installed. The release in question should be made available in the next few days.
Upgrade to this version once it's release and checkout whether the new feature will do the trick for you. Let us know if you still require out assistance after that.
All the best,
the Telerik team