I was thinking robots such as in Pacific Rim where they are advanced but are in the realm of realism. 

Such as these:  

http://www.panicfilms.com/wordpress/wp-content/uploads/2010/07/and_outcome_the_wolf_by_ahbiasaaja.jpg 

http://farm8.staticflickr.com/7454/9231660080_8aeecf169b_b.jpg  

http://lockdownvii.deviantart.com/art/Pacific-Rim-Jaeger-Lockdown-390086745 


I was also thinking all nations would have their own mech some like the US would have a few while nations like Panama may have one.