> My biggest problem with using Unicode is that it's often a pain to type.
Agreed. We might be able to add a hook to arc-mode in emacs to make it more convenient, but reminds me even more of APL (which if I recall correctly required a custom keyboard to type).
> + might not be bad, but it's probably a little too common
I like +. While + does get used in symbols occasionally (most notably in arithmetic), I can't think of any cases where it gets used in the middle of a symbol.
EDIT: On second thought, when I use plus outside of a programming context, I usually mean and, so it might be confusing to use + as 'andf.
The problem with "adding a hook to arc-mode in emacs" is that then you alienate everyone not using Emacs. And that's a good point about + being used to mean &.