Hey, finally something I'm an expert on. Fenggar was originally a disabled Dwarf in a steam-powered wheelchair. He was only available in the Brotherhood of Bronze box set, which is several years OOP but still pops up once in a while. Here he is:

His "Fist of Bronze" incarnation, sold as a mail order exclusive, is really just half of the model pictured above, combined with the "chassis" from this goblin hero, Golborak:

and the arms from one of these fellows, also from the B.o.Bronze box:

That is a 25 mm base he's pictured on, and he's about 4 cm in height.
Mine isn't for sale, sorry. Just thought you might like some background on the components used to put him together, as I doubt the mailorder offer will ever return.
I see that chariot for sale on discount all over the place, but I think it's a bit large to use for a Deathroller, even without the boars.