The sugestion of Dwarf and beast teams instead of Bear riders, sounds interesing. Would it sit with the Fluff, and what sort of beasts are we talking about, Bears, wolves, Pitbulls?
I think the norse vs steampunk in one book is a good idea, though steampunk sounds a tad shoddy, a bit Skaveny. It should be precision engineering.
I can also see Dwarves carrying more things into battle. Anvils, More thrones!, Rune altar of Grungni/Valaya/Grinmnir, Keg of Power.