No trying to detract from your greater point, which I agree with, but...

T-Mobile sells the Nokia Nuron, which runs Symbian S60 and has 3G, subsidized.

You can also get phones directly from Nokia (or from non-carrier stores - even Fry's has them) that work on AT&T's 3G, and a couple that even work on T-Mobile's 3G.

None of them are advertised as "Symbian phones", though, just as "smartphones".