[PhilD]

No nations have anything really like "dragons" as national units, I believe. If you want some, you'll have to summon them.

Wyverns are a lowish level Conjuration, requiring Air 2.
Iron Dragons are a level 9 Construction, requiring Earth (3? 4?), and, of course, much stronger. Those are the summons most dragon-like that I can think of.

As for rainbow mages... if you're thinking about your pretender, any nation can play with the human or human-like, weak as hell, low-path pretenders - so any nation can make a rainbow pretender.

If you're thinking of national mages... I have to admit, I haven't tried enough nations to know. Doesn't Tien Chi have national mages with many elemental paths?