A quick update for people who haven't been tracking git closely: The Julia REPL (#6911), IJulia, and (soon) Emacs julia-mode (#6920) now allows you to type many mathematical Unicode characters simply by typing the LaTeX symbol and hitting TAB.
e.g. you can type \alpha<TAB> and get α, or x\hat<TAB> and get x̂. There are currently 736 supported symbols (though not all of them are valid in Julia identifiers). This should provide a consistent, cross-platform Julian idiom for entering Unicode math. Hopefully this can also be added to other popular editors at some point, e.g. presumably vim can be programmed to do this, and there is a somewhat similar mode for Sublime (https://github.com/mvoidex/UnicodeMath). (Less-programmable editors might need source-level patches, but it doesn't seem like an unreasonable patch to suggest.)
