So I was pondering ways to get a Surfing Pikachu other than using Pokemon Stadium and I came to this idea:

In GSC, when breeding, the father could pass on both TM and HM moves (I'm not sure if HM moves still get passed on in later games), right? Well, what if you had a male Smeargle that had Sketched Surf and bred it with a female Pikachu? Would this produce a Surfing Pichu?

I don't think so, because Surf isn't in Pichu's egg move list.