I have put an old savage orc on a (scotia grendel) hydra. (back in 4th ed. that was legal). Have not done anything with my lizzards yet, but a hydra would certainly work imho as a replacement for a steg.
That sounds very cool! Do you have any pictures of him. Btw, who thinks that coatl's gonna be the big (model) rare unit for the next lizardmen army book? Regarding alt. mounts one thing that comes to the top of my head is warplocks kiwi riders which you can find in this forum thread http://warhammer.org.uk/phpBB/viewtopic.php?f=4&t=56472&start=30 I've also thought about ordering and make something of this beast http://www.reapermini.com/OnlineStore/turtle/sku-down/65132
Hey. I did some conversion of stegadon from some toy dinosaur (I believe it's ankylodon). Unfortunatelly no pictures yet. And I remember that guy Totzro mentioned. He also runs his own miniature company and actually sell those deadly kiwis: Warploque. I am (was) also working on frog hoppers (skinks on giant frogs)... But that project is "dead" for almost two years... Hmm... Maybe I should get into it again
Way back before our current book, I had a plan to create an EotG out of this figure: (Keep in mind that it would have been slightly larger than a Stegadon, since Stegadons back then were substantially smaller than they are now) I ended up never doing this conversion because GW came out with the current EotG model.
I built 3 Engine of the Gods using a T-Rex, Stegosaurus, and a Brontosaurus from other manufacturers. They actually are my center pieces to my army. They get me some of the biggest attention when I get the paint scores. I also mounted my Slann on a great tortoise. I am currently working on a Lord Mazdamundi using the Ogre Stonehorn model. I may also be putting a Saurus Oldblood on a Juggernaut. Just because I think it would be cool with putting Lizardmen icons all over it.
I did a Salamander conversion from the 5th Edition model as a center piece for my unit. Here's a pic sorry not the best quality
here is the image of Tiktaq to on the coatl. i thought this would be the most fitting model to have ride a legendary monster http://s508.photobucket.com/albums/s327/ssj_brolly499/?action=view¤t=tik.jpg
pity about the camera focus there... I am planning to mount a siege tower on top of a toy snapping turtle (if I ever get to the point in my campaign where I can actually mount a siege...)