Really? I take your point to mean that two smart people can communicate better using obscure vocabulary when they are communicating only between themselves. High baud necessarily implies higher average information throughput, so there would have to be a significant number of these words in the communication.

Could you point to some examples of letters between two famous people using this method?

Most notable people seem to prefer simple vocabulary, and in fact, many of them go so far as to recommend it. The people who prefer complex vocabulary (cultural studies journals, intellectuals) do not seem to accomplish anything of value, and indeed they are routinely accused of being obscurantists.

(Ground rule: scientific jargon excepted, since it is not a part of the vocabulary. But, feel free to look at letters by Newton, Einstein, Godel, Hilbert, anyone really.)