I've ordered myself a second one of these:
One of these just popped up on Amazon for $30 in Used Very Good condition while I was in the bathroom, and I bought it. Hope it works, because it was the only listing, and I can't find it or any other actual six-face-button dual analog controller anywhere else online other than a pre-S-Type original Xbox controller (the S put the black and white buttons in a weird place that would defeat the purpose of using it for N64 and Sega emulation).
(I thought I found one for $10 that looked just like a tiny little Dualshock with 6 face buttons, but the sticks are actually just duplicates of the D-pad and first four face buttons, and there's no Start and Select buttons, so effectively it's just the pre-analog PS1 controller. No one makes controllers like this anywhere as far as I can tell, which is weird because the fact that someone made that $10 one that tricks you into thinking it's one definitely shows there's a demand for it.)