Nice - thanks for the images, it is very helpful!
In New England, there is also a PFS brand called "Mystic White", with a #20 mesh grain size. It is REALLY white - much brighter than the Fairmont, even. Someone near Wisconsin mentioned Red Flint Sand. According to their website, they offer several different mesh sizes, AND an aquarium sand, which seemed to be about the size of play sand grain-wise. Of course, there is nowhere near me that carries the Red Flint sand (which I've coveted for years now), but it looked lovely. Their standard PFS is a nice warm light brown, and they even offer garnet sand, with a burgundy undertone or hue - actually looked much nicer in a planted tank than it sounds like it would.
I've also played around with the Quickrete "General Purpose" sand, which has a huge variance of grain sizes. I sieved out the larger particles to use (LOTS of dust/dirt, bleah), trying to get a darker riverbed look with rounded or worn grains of various sizes. Came out pretty nice, but the portion of the bag that was the "desired" sand was probably less than 25%, and it was quite laborious to sieve and then wash enough for the little nano tank its in. See - you're not the only one who gets rather OCD about their sand, LOL!
Please post pictures with the sand you decide to use when its in the planted tank - I've subscribed for any updates on your SAND QUEST!