EDIT: I would prefer that people keep what parts do and don't share molds in mind for this. On that note:
Metroplex:
- Head antennae, rifles, double-blaster, Six-Gun's torso
- Thighs, left half of torso, toes, shoulder turret, missile battery (it's white under the chrome), shoulder antennae, Slammer's turret, Six-Gun's chestplate
- Arms, calves, kneecaps, middle of torso, right half of torso, waist, mount for shoulder turret, back tower, Slammer's body
- Head, mount for missile battery, torso garage ramp/door, torso garage launcher, fists, missiles, rifle triggers, rifle connector cuffs, button that deploys head
Trypticon:
- Head, outer body, outside of tail, arms, legs
- Hip covers, nose cover, Brunt's laser
- Brunt's other pieces, forward ramps
- Full-Tilt, claws, side platforms, heels, tiny tower/cannons, barrels of shoulder cannons, knee centers, battery covers
- Inner body/inside of tail, inner pieces of legs
- Shoulder cannons, soles of feet
- Full-Tilt's gun, radars/turrets
I personally think that a G2 Trypticon might have been colored similarly to his BWII redeco & retool Gigastorm, since Gigastorm's original form, Megastorm, was a veeery slight redeco of G2 Megatron. Still, that's only one idea.