Here's the initial ideas for Karkadann armour, Fallen Dwarf style.
No laughing please, I've not committed enough time to develop in the digital art space!
Thematically this is heavy linebreaker assault cavalry. I've consciously gone for a larger mount for the Dwarves instead of the usual pony/goat/pig cavalry trope associated with the race.
I'm still undecided so more sketches are required, though I think the large crossbow mount is off the table... in favor of a huge crossbow towed along on it's own carriage by the beast.