TITLE: Where could (do?) we go after exhausting greek letters?
QUESTION [7 upvotes]: I'm still in high school but after all my various math and science classes including calculus, statistics, geometry, and physics, I think that we've pretty much run the course of both upper and lower standard letters, and upper and lower greek letters.
The problem has become more apparent to me in statistics, where there seems to be an absolutely ridiculous amount of variable overloading in various equations.
Where could mathematicians go for new symbology to lessen this overloading? Greek letters are nice because they are foreign enough to most people that they seem appropriate for math yet familiar enough that they do not distract from the math in the way a more artistic lettering like Arabic would.
What is an alphabet with enough unique characters in it that is feasible to use in such a situation?
Is there any kind of push for such a thing?
I mean, I understand that context is the biggest identifier in symbol meaning, but at some point as concepts gain importance, these symbols become somewhat like a reserved symbol, such as pi. 
You'd get some confused students if you tried to use upper case sigma or pi as a standard variable.

REPLY [3 votes]: Why stop at alphabets?
There are over 74,000 currently defined Unified CJK Ideographs is unicode. 
For that matter, why stop at written representations of standard languages? Symbols from music have already been widely accepted in differential geometry, and the comprehensive LaTeX symbols list contains many more possibilities: a close friend and collaborator of mine has managed to sneak lightning bolts (see pp 18) into an actual journal publication. 

Symbol overloading is not as big a problem as you think, by the way. To take your own example about $\Sigma$ and $\Pi$, it appears you are not familiar with descriptive set theory.