I think a chariot could fill the "Gore-Grunta"-style heavy cavalry role well.
- two Cold Ones drawing it
- a Saurus Warrior who steers it
- a Saurus Warrior or two fighting with spears and carrying shields
"Saurus Knights on Chariot" stats:
- Three chariots in a unit, Move 7", 5 wounds each, 4+ save, Bravery 10
- ignoring rend -1 like all Saurus
- 3 attacks with the Spears: range 2", 4+/3+/-1/1
- 4 vicious bite attacks by the Cold Ones: range 1", 3+/4+/-/1
- point cost ~140 points per three models
- has the keyword "Saurus Knight" so can be used in a Firelance Starhost and be buffed by a Scar-Vet.
As you might have noticed that's almost exactly the Gore-Grunta's stat line except:
- slower by 2", so the same speed as Saurus Knights
- Vicious Bite's hit is 1 better than the Gore-Grunta's hooves.
- the rend -1 immunity
- no charging ability, but to be honst: The one from the Gore-Gruntas sucks as well, I have never seen it used
I think that could be a nice unit.
I'd also like to have a Seraphon hero chariot:
- two Cold Ones (or Horned ones, with a charge bonus) drawing it
- a Saurus Warrior who steers it
- two versions:
A: a free space on it that allows to put any non-mounted hero with a maximum base size of 40mm to be put onto it. Like an Oldblood on foot, a Sunblood or so. While the hero is on top he can fight normally but use the chariot for measurement and cannot be targeted separately. He can leave the chariot like Kharadron Overlords leave their transports. That version could be nice for cavalry armies, transporting their favourite heroes with a bit of protection and especially with enough speed to keep up.
B: a Priest of some sort, providing a 10" buff bubble (heal, ward save or something like that) for some types of units (like all Saurus units or so). This would be the support version meant to accompany Saurus Knights.