While searching for rare Elvis photos I came across the site dedicated to Debra Paget: http://www.debra-paget.com
On this site you'll find some Love Me Tender photos in good quality, some pics from the June 5, 1956 Milton Berle Show, a four minute clip of that show, but - and this really attracted my attention - also a real 3D picture from the fifties of Debra in all her glory:

You'll need your red/blue glasses to see the 3D effect.

This find made me wondering if there were real 3D pics of Elvis as well. So I googled and came - between other things - across this topic on FECC:
http://www.elvis-collectors.com/forum/viewtopic.php?f=8&t=51370
In this topic a Stereo Transparency made by Joe Pulliam in Feb. 1971 is shown through a post by drjohncarpenter:

Out of that Stereo Transparency JamesVRoy made this anaglyph (again you'll need you red/blue glasses to see the 3D-effect:

By my knowledge this is the only existing real 3D anaglyph of Elvis at this time. (Don't know if more were made out of the ten existing stereograms of Joe Pulliam).
The 2D-version was used for the cover of this CD:

Unfortunately a lot of pictures and links in this topic from 2010 aren't there anymore. With web.archive.org I tried to find the auction with all ten real stereograms of Elvis in Feb 1971, but with no luck.
In my personal archive I found some pics of them though. I didn't even remember I had them. It looks like they are from Feb. 26, 1971 - they are dated:
Meanwhile there are also a lot 2D to 3D conversions to be found. Footage as well. They can be beautiful too, when it's properly done. But I really belief that the Stereo Transparencies shown here are the only real 3D pics that exists. If you know there are more, please let me know.
An example of 2D to 3D converted footage that's properly done in my opinion is this:
..
But many bad examples exist as well. We all remember this disaster:

With images like:
To close off this topic here is another real Elvis related 3D image (anaglyph). It's not Elvis. It's Elvis in Wax. Just to give an impression of how it might have looked if the 3D technique was used a little more often on Elvis while alive:
.