Nords get lots
Argonian some from other argonians?
Faendal make comment if elf
Orcs in strongholds
Caravans for khajiit?
I think it has to do with the fact that half those hairy nords can't do the simple math: Imperial =/= Empire supporter. The Bretons I don't know, probably because those terrorists in the reach are Bretons.
I know alot of Nords will make positivie reactions if you're playing as a Nord. Never done an Imperial so I couldn't tell you. I don't see why not though.
I don't remember getting recognition as a Breton, but I don't think I've never gotten any.
Except for a rare few who dislikes EVERYONE not of the same race as themselves, most people seem to be neutral towards Bretons and Imperials. Of my 7 playthroughs, five have been with Bretons or Imperials for some reason, and I can't remember anything special.
Which I've always found it curious that the Forsworn didn't pause and ask the Breton's allegiance or that Ulfric doesn't mistrust them more than Argonians and Bosmers combined.