The Manka-Class Armored Transport, or Manka Walker for short is a very well known ‘Turtle’ style walker seen throughout the entirety of SWTOR in Republic locations.

However in the Beta and old story trailers for SWTOR, we can see a much different design of both Republic and Imperial walkers used across the Galaxy.
While many know the Manka Walkers today to look like this:

The original Manka Walker sported an AT-TE design with a large Hoth style turret affixed to its top. It was most noticibly seen in high detail and close up in a preview trailer and wallpaper for the Jedi Consular from SWTOR in 2009/2010, years before the games release:

You can still find the Beta version of the Manka Walker today! It can be found at the very beginning of the Battle for Ilum, on the horizon, as you take the speeder from the starting location to the first trenches of the Flashpoint. On the opposite side of the distance you can even see the Beta Imperial-Walkers with round bodies and large tank treads instead of the square and upright walkers we see in SWTOR.