Now this can hardly be considered confirmed (for it is from the people who can't play and all), but they claim to have actual boss names for Rush that kinda make sense, sorta.
Translating them into something generally readable (and correct as far as levels), as well as my comments on validity:
Leaf Storm Boss = Egg Hammer Mega (Makes sense; Egg Hammertank (II) from Advance 1 and 2. Though mega is really lol.)
Water Palace Boss = Egg Turtle (Looks kinda like a turtle... sorta.)
Mirage Road Boss = Egg Scarab (Based on appearance, this is likely correct.)
Night Carnival Boss = Egg Libra (It pretty much is a scale. All I can really say.)
Huge Crisis Boss = Egg Hammer Fortress (I'm not as sure about the fortress part, even though it uses the battleship for launching the cannons. However, it is awfully close to Hammer Mega, so still logical.)
Altitude Limit Boss = Egg Eagle (Somewhat what I thought when I first saw it, considering Egg Hawk is already taken by that atrocity in Heroes. Yes, I said atrocity.)
Dead Line Boss = Blaze/Sonic (As if this wasn't blatantly obvious. Also randomly this is a fun fight.)
Unknown = Egg King (I almost just say WTF here, but meh. I'm pro this staying Unknown.)
Exception = Egg Salamander (I haven't seen it yet, so I can't comment. However, see Unknown anyways.)
(Link to actual post)