User blog comment:Xaero Dumort/Just announced: Mass Effect 3 : Retaliation/@comment-1786741-20121005180140/@comment-4721065-20121007072024

And what makes you think that some other race will be designning these suits instead of the volus themselves? They're experts at reverse-engineering technology and ME had a line of volus--designed armor and weapons. I could totally see volus getting their hands on on a few wrecked Atlases/YMIR and modifying them to suit their needs. Not to mention that their small size makes them into excellent pilots, since there would be more space left for the weapons, engines, power cells, shield generators, etc. It is entirely possible that since other races don't have Cerberus know-how, they cannot design a functioning suit of their size.