Endurolytes is another option without the flavors, sweeteners and fizzing agents.

Polyethylene glycol isn't the safest thing in the world, I agree, but that it's "found in [low-toxicity "green"] antifreeze" isn't really relevant... so is water. I''m equally concerned about the acesulfame potassium (which is not in antifreeze). I will use Nuun as a "quick fix" - if I do make a homebrew I make sure to include potassium, calcium and magnesium in addition to the sodium - and personally I can't tolerate any fruit or fruit juices during a ride or run. YMMV.