Syntetist Summoner/Alchemist: Evolutionist
A class that selects permanent evolutions, becoming more and more like a monster (or more civilized combinations).
All classes/All classes: Unbound
A modular class that selects class abilities based on points, capable of becoming anything.
Druid/Oracle: Avatar
A class that receives innate powers from nature, controling its elements intuitively.
Monk/Sorcerer: Bender
A supernatural martial artist focused on one element, whith "at will" powers regarding that element.
Monk/Wizard: Swordsage
A mystical warrior proficient in martial arts and a few but powerfull spells. Also has access to several supernatural "at will" powers (telekinesis, Telepathy, Precognition)- a jedi.
How about archetypes of the Cleric, Druid, Magus, and Witch classes that use the Arcanist method for preparing and casting spells?
Barbarian/Druid: Rageshaper/Wildrager
Cleric/Monk: Friar
Druid/Witch: Hierophant
Alchemist/Summoner (synthesis): Artificer/Ironman
Sorcerer/Witch: Sibyl
Rogue/Sorcerer: Trickster
Cavalier/Witch: Hexblade
Druid/Inquisitor: Warden
Paladin/Ranger: Mountie
Alchemist/Babrbarian: Hulk
Fighter/Rogue: Bandit/Thug/Brute/Swashbuckler
Druid/Rogue: Beastmaster (animal companion as flank buddy/Teamwork feats)
We could just go over to the MCA wiki and copy the archetypes that we would like to see made "official".