Sadly, there has been comparatively few developments in keyboard hardware and input schemes since the 60s.

Huh?

On DE-International that is on [AltGr]+[Shift]+[,]: ×

Julia has support for unicode in the language (unicode identifiers, etc) and even has some operators/functions (they are the same thing in julia) aliased as their usual symbols, like "in" is aliased to "∈".

[0] http://docs.julialang.org/en/release-0.4/stdlib/collections/...

That doesn't look very different from the letter x though, I think I'd still prefer the asterisk even if there was a × button on my keyboard.

There has been a × key on the normal PC keyboard since 1986, on the numeric keypad section.

[citation needed] I'm looking at my 1992 Model M right now and it has just a "*", unless you count "+" as a lopsided "×".

Depends on the manufacturer – some, like a Keytronic I can see from here, definitely have a × glyph.