I don't think I'd like single serving packaging very much. I do what exdiver does on a smaller scale I guess. The packaging would just be extra garbage for me to deal with. I don't even use single serving hot cocoa, especially because of the foil...
I still actually like Kool-aid so I use the presweetened type repackaged w/ a small, ~2oz plastic bottle w/ a screw-on squirter cap. I can get maybe 10 packs or 20 quarts in the bottle, it's light and packs small enough to keep anywhere. I even take a spare on longer trips. If it's really hot, I'll add some complimentary flavored yet oh so HEAVY Gator-Aid (kept in a zip-loc in the day food bag due to volume) simply for the electrolyte boost. It's nice for varieties' sake too. I just squirt or pour either in till it suites my thirst at the time. I'm not fond of plain water at all!
Did I tell ya 'bout the time...
My wife and I were beginning a portage. Our juice bottles are snap top, quart bottles kept in often wet, insulating cozies. Anyway, I took a drink and stuck it back in the day food pack that was already on my wife's back and she was on her way. Seems I closed the cozy but, ummm, forgot to actually snap the bottle shut. That particular pack isn't waterproof at all.

She said that once she figured it was cherry Kool-aid and not watered down blood trickling down her back, she actually didn't mind it so much. ...felt good on a hot day I guess. Lucky for me it was a hot summer day. She forgave me. I doubt I ever will.