Every one I order seems to turn up pink or very dark red! I am after one in a shade that matches a Swiss Army Knife as that is what I am hoping to pair a couple of lights with. Call me pedantic but I was trying to build up a couple of sets to go into pouches. One for me and one for my son for his Scouting.
http://www.ebay.com/itm/Hi-Quality-SK68-Q5-CREE-LED-Lamp-Portable-Mini-Flashlight-Torch-Super-Bright-New-/371339603197?var=&hash=item567590acfd (also seems to shine red)
If you are willing to compromise on the single-cell, have you considered the Red Maglite? Even that’s a deeper red than a SAK though.
Unfortunately, you are right… too many budget red flashlights turn out to be purplish/plum. And quality single-AA lights are a bit rare.
2xAAA and out of stock, too bad. Might find them somewhere.
This 1AA LRI Photon Proton, has a nice red, as does the 2AA Fenix HL-30 headlamp.
http://www.amazon.com/LRI-PPRO-Proton-2-Colors-Flashlight/dp/B001CZ9CCO
There’s not much of a choice, as google reveals.
Most offers are SK68 clones, they are cheap but have an abysmal beam profile.
Next problem is, that with flashlights red often isn’t red (like in Maglite Mini Cool Dark Red) but more of a pink color.
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Best one for ages was a host that cnqualitygoods sold.
B1 1xAA Red Shell Flashlight Host Kit
Some assembly required 
But afaik it’s not sold anymore.
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Best thing I can come up with is the Solarforce Z2, which comes in some kind of red as well.
Yes, my red SK-68 clone was nice and bright.
The L3 Illumination L10 is available in red…………
Check out the Xeno AA light. Comes in red, blue, and a few other colors. It is a non PWM light. It uses CC so no flickering.