I have confirmed with multiple players that you show up as a human on everyone's screen, not just your own. This is server side.
You will need:
1) A shapeshift mount (i.e. Sandstone Drake, Obsidian Nightwing)
2) A Blingtron 4000 to be dropped outdoors (anywhere you can mount up)
Bind your mount to a key or you won't be able to do it fast enough. Right click Blingtron and click the "Let's Party!" dialog option and immediately hit your mount keybind. If you are quick enough you will mount up but remain in the human form that Blingtron casts on you. On the ground, you stand on all fours. If you run on the ground, your character stands up and runs at full mounted speed. In the air, your character will fly using the swim animation. You can /mountspecial to have your character stand up for about 5-6 seconds while standing still.
Extra notes: You can make a macro and keybind it to click Blingtron's dialog box so that you have an easier time getting the mount cast off quick enough. Just type this into a macro: /script SelectGossipOption(1) After you've already completed his daily quest and right clicked him again, this macro will automatically click the button for you.
I know this isn't the most useful of exploits, but it's definitely fun to fly around the city like this!Have fun!
Edit: If this is a repost I apologize but there are so many posts made about mounting without showing the mount that it would have taken me all morning to check all of them so I figured I might as well post this since I figured this out on my own just now and tested it myself.