Howsabout a team of mechs based on some of the arthopod kaiju in Godzilla's rogues gallery. Going for a land ,sea, air motif I'd think a Mecha-Kumonga(Land) ,Mecha-Ebirah(Sea), and Mecha-Megaguirus(Air) would rule the roost. Partial credit for that goes to the Lizard Slayer mechs from the episode of GODZILLA:THE SERIES
, "Lizard Season"
The idea of cyborg kaiju also works fine for me as well. Mecha-King Ghidorah has always been a favorite of this fan. Likewise Cyber-Godzilla from GODZILLA:THE ANIMATED SERIES.
In fact, when Dino DeLaurentis made his remake to King Kong
. It was intended to be the first of a trilogy of flicks, and the follow up to first flick was intended be called BIONIC KONG
. In which the big ape was to be resurrected as a cyborg by a group of criminally motivated scientists, and is even made to kill Dwan by them. But it never happened ,but some elements were included in KING KONG LIVES.
He probably would've ended up looking like this bloke in the flick.