Modular Character design, How to have variable limb sizes.

Im working on a robotic character which is completely modular. i.e. you can swap out helm, spaulders, torso, fauld, arms, legs etc.

Generally the components all fit to the same skeleton so there is no issue with the joints aligning, however i would like to be able to have larger limbs as well. Is this possible using the same skeleton I thought about having multiple skeletons but that would mean i would have to have a differant skeleton for each configuration.

I’m wondering if the skeleton itself needs to be modular? i.e. the arm, torso, legs all have their own rig then place them together in UE4. (though i suspect that’ll be a nightmare to animate)

I’ve googled the living day lights out of this and cant find a resolution.

Can anyone give me any advice on this please? I haven’t dealt with this sort of thing before, any help appreciated.

Image, in case i haven’t explained myself well. First three images show what i have now, forth shows what i would like to do.