Iron Fists are pretty cool, but I reckon White Scars. I've always liked them. I know they're the biker guys, but still.
Should be a bit of a challenge to paint well too, as flat white can be tricky.
As to the Pardus Titan, I wrote up a list for the Khureshi, which are tiger-men in the East. They're sorta like noble beastmen. Anyway, the Pardus Titan is one of their Rare Choices and is easily the coolest thing on the table when completed.
I'm gonna convert it from the Giant kit, but it involves massive amounts of sculpting.
As far as stat-line goes.
M WS BS S T A I W Ld Pts
6 5 - 6 6 5 5 5 8 200
Hand Weapon and Heavy Armour
May take one of the following options:
Additional Hand Weapon - 10pts
Great Weapon - 15pts
Shield - 10pts
Lightning Reflexes: The Khureshi are creatures with a naturally high metabolism, the fastest among them displaying reflexes that give some credence to the rumours that the Khureshi can glimpse into the future. When charged, the all Khureshi will still strike in Initiative order.
Of course the book was written with 7th Ed in mind as our group does not play 8th. As a whole we are against the changes.