E. Halibut
Gamera
Personally if mud is fine I'd just airbrush the whole friggin' underside, hull, track, wheels and all with mud coloured paint! Maybe just leave some blue showing on the suspension bogies.
One of the most head-scratching things I ever saw was in a magazine where someone was building a Pz. III and was painting all the wheels and tracks separately. He went to the expense of using commerically-manufactured masks to cover the hubs while he sprayed the tires a rubber colour. Then, after the wheels and tracks were added to the model, he covered everything in such a slurry of pigments that you couldn't tell that they were ever different colours.
Personally, I've found that I have trouble painting AFV tires on or off the model, so I usually assemble everything, because I don't like putting glue over paint.