Are US ham bands really symbol rate (rather than bandwidth)limited?

Here in LA (Norway, for the ham prefix challenged), we can modulate in whatever way we feel like on 2M, as long as the signal bandwidth does not exceed 18kHz.

(So, using a clever modulation scheme, you could get very close to the Shannon limit for the given channel bandwidth and noise level - assuming a very healthy 30dB S/N, one should be able to wring approx. 180kbps from an 18kHz channel. (Granted, in the real world with filters without infinitely steep skirts we'd get nowhere near this - but, let's say you could get 1/3 or so without trying too hard.)