I've been pondering making a Kaban Machine at some point in the future, so was crawling the internet looking to see if anyone else had made one. And I stumbled across a beautiful Dark Mechanicus army made by a chap called MrManson.
You can find it here: http://www.dicelikethunder.com/forums/viewtopic.php?f=27&t=1839 or here: http://www.dakkadakka.com/dakkaforum/posts/list/253378.page
I love the paint job on these guys, dark with glowing firey runes. Nice! And the models are very very interesting. Clearly I'm going to have to buy some Empire Wizards at some point to make cool Techno-Magi...
The two Praetorian Ogyrns are all sorts of awesome, I'm itching to combine one of the ogres from my bits box with my Assault on Black Reach dreadnought legs now :D
Finally there's his Kaban Machine. Wow. That's a cool looking beasty, combining the body of a Defiler with the tracks of a Russ. I'm tempted to follow a very similar route. The Defiler's legs are bound to come in useful for future Knight Titan projects. I may mount it on smaller tracks though, I always pictured the Kaban Machine as being mainly about the huge torso. Possible Ork Trakk tracks could work? And I've got lots of them lying around, so it'd be a cheaper project that way!