We decided to start with the Age of Sigmar Ironjaws Warboss, because the armour would seem more delicately shaped, and more 'teef paid for' than Big-G's very rough but durable gear.
(For those unaware, Ork money is, literally, their teeth. No dumber than bottlecaps!)
The head is off a Flash Git, turned to face the right direction, and hilariously, happens to be a head with no big teeth, almost as though Nazdreg is constantly getting rid of the oversized ones to pay for more flashy gear!
The right arm saw extensive conversion: Axe removed, replaced with a gun from a Mek, itself modified to be pistol-gripped, with an appropriate Bad Moonz symbol. The forearm is mostly untouched, but the upper arm is a complete putty resculpt from bicep to shoulder, including custom shoulderpad from plasticard and more Flash Gitz bits, as well as bass guitar strings.
Nazdreg's backside: More flash gitz bitz to make a crude power supply for this huge armour, snaking cables connecting upper and lower torso, and more mechanical gubbinz supporting the leg armour. You can also see the power feed down the right arm.
And my favourite part: the Klaw! Entirely plasticard and putty, it imitates the shape of any other Orky piece. I may put up some in-progress shots, but it's pretty straightforward: Fist-shaped box, festooned with sharp fingers, backed up by pistons, and rammed full of bizarre and arcane power leads back to the mysterious (fusion?) power source.
And there you have it! Quick and dirty Ork conversion, still with lots of room for fun and bizarre painting details. All in all I think he makes a nice contrast to Ghazghkull's angry striding, feels very Bad Moonz (Lookit' my Flashy Shoota!) and looks just a little bit fancier than just a regular megaboss! I'll put up painted pictures when I get them from the client, no idea when that'll be!