I made these fellas a few months back and haven't quite finished them yet but this is just a few pictures to show how far I got. I'll put the images in spoilers because they are quite big.
EDIT: Why is that MKIV hand so huge anyway?
This is the first shoulder pad I sculpted and I used this on the first lot of Iron Warriors I did but I thought it looked a bit rough so I did the second one as shown below.