This Ultron was heavily inspired by Jin Saotome's custom that was in turn inspired by a 2013 SDCC teaser exhibit from Age of Ultron. Techniques employed credited to Automatauntaun, CosmicFantasyCustoms and my own! Figure features include up to EIGHT arms and numerous configurations of swappable limbs and weapons.

Here is my recipe:
Lower arms - Iron Man Armored Avenger Titanium Man
Middle arms - ToyBiz ML Dr. Doom
Pauldrons - ROML Extremis Iron Man
Upper Arms - ML Face Off Red Skull
Sword - LEGO Hero Factory
Guns - Star Wars and 1:6 fodder
Energy Blasts - various
Hydraulics - Apoxie sculpt over Revoltech stand segments

Details:
Took an IM3 Legends Ultron, dremeled the heck out of his torso sides and attached some ball pegs from Marvel Select fodder then added arms from Titanium Man. Dremeled back even more and added Dr. Doom arms. Dremeled out upper housings for upper back Revoltechs. Modded lower and middle limb housings and packed with Apoxie for a snug fit. Also modded shoulder ball joints for pauldrons.

Lower and base arms feature swappable hands and can receive the Revoltech joints. Middle and Upper limbs are also removable for a variety of combos. With the extra limbs and Revoltech joints this fig has over 70 points of articulation. Totally repainted with Model Masters Acryls, Gundam Markers and DecoArt paints and then sealed up with ModPodge and Krazy Glue.

Thanks for looking and God Bless!