Is ...Na6 in the Caro Kann considered in any of the SOS books?
If not it would seem to qualify, as 2...Na6 has been played several times by Serbian GM Markovic, including this year, and a few times in the past by Tony Miles.
It seems like on move 2 it's often a prelude to a setup with ...g6. However I think a later ...Na6 may also be theoretically significant in the 2. d4 d5 3. Nc3 dxe4 4. Nxe4 line.
4...Na6?! is possible right here, but where it's actually gotten a look from a GM is after 4...Nf6 5. Nxf6 exf6 6. Nf3 and now 6...Na6 -- Czech GM Lechtynsky drew with it against Wedberg in the 1980 Malta Olympiad (and a 2300 drew with it a few years later against GM Unzicker)
I got to looking at this because if I play the Scandinavian line 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qd8 4. d4 c6 White can transpose into the CK with 5. Ne4?! I'd like to play the immediate ...Na6 to tamp down how much theory I have to learn, and then possibly transpose into the line from the ...Nf6 variation above after Nf3 ...Nf6, but I'm afraid there may be some way to punish 1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Na6?! (and of course there have got to be better ways than 5. Ne4 of trying to punish 3...Qd8 and 4...c6 in the Scandinavian, but that would be another topic)
Thanks in advance for any pointers, right here in the forum, or in any published references.