Correct - there's a Ghar Command Crawler and a Ghar Bombard Crawler in the main rulebook, and a Ghar High Commander Karg crawler in the Xilos campaign book. Oh and a smaller one called a "creeper" for rebel Ghar.
The Bombard Crawler has, you guessed, a massive gun on the back of it. Just like several AT-43 crawlers!
A search on "ghar crawler" should help you with the size and shape of the models