Conversion Corner: CSM Sorcerer on Bike WIP

With the release of the Crimson slaughter codex, I've added a Chaos Space Marine sorcerer on a bike to my Kublacon list. Divination is the bee's knees. As my CSM army is Nurgle themed, I didn't want to just convert a Chaos Bike to have a sorcerer on it. That bring us to the Corpse Cart. Really cool model, obviously oozing Nurgle (quite literally), and perfect for a Sorcerer to ride into battle. Here's the problem though:

The corpse cart fills a chariot base, but needs to fit on a bike base for my CSM army. The picture above illustrates the difference in size, which is significant. The base is an Urban Rubble bike base from Secret Weapon Miniatures. My plan is to build the cart without the yolk and without the wheels and build a tank tread unit under the cart and mod some sort of engine to it. Won't have to be too sophisticated as it's a Sorcerer's ride and much can be explained away by MAGIC!!  Making it look like it runs on decaying body parts will be fun though!